diff --git a/lib_com/options.h b/lib_com/options.h
index 2b2ccec9b5bf38b4fb29f383fec7f0b457a730ac..8cfd1dc741bc64766fb42acb602b483cfb2fc01c 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -154,6 +154,8 @@
 #define FIX_BASOP_2562_HQ_PREECHO_SAT                   /* Eri/Orange: Basop issue 2562: Add saturation to L_add in preecho calculations */
 #define FIX_BASOP_2561_STEREO_DFT_ENC_COMPUTE_ITD       /* BASOP issue 2561: fix diffs in stereo_dft_enc_compute_itd() between float and BASOP */
 #define FIX_BASOP_2517_CLICK_IN_OMASA_LTV               /* FhG: BASOP #2517: preserve precision by removing one-bit headroom from Q_min and allowing saturation during buffer scaling */
+#define NONBE_FIX_ISSUE_2518                            /* FhG: Fix issue 2518, noise during ACELP switching from 16KHz to 12k8Hz by improving Q_new calculation. */
+#define NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX           /* FhG: Fix issue 2518, fix wrong amplitude because of saturation of x_tran in transf_cdbk_enc_fx() for transient signals. */
 #define FIX_BASOP_2559_Q_SYNTH_HISTORY_RESET            /* FhG: BASOP issue 2559: reset hTcxDec->q_synth_history_fx in allocate_CoreCoder_TCX_fx() */
 #define FIX_FLOAT_1578_OMASA_REND_SPIKES                /* Nokia: Float issue 1578: Fix spikes and collapsed perception in OMASA/MASA rendering to FOA/HOA */
 #define FIX_1521_SBA_LOUDNESS_STEREO                    /* FhG: issue 1521: Fix loudness for SBA to stereo rendering */
diff --git a/lib_enc/acelp_core_enc_fx.c b/lib_enc/acelp_core_enc_fx.c
index 5949ce99f57ba77a968a0a45fccd6731f68ec4db..5f38e5bd374a43f5ab6bcb754be4c4bc2ca77128 100644
--- a/lib_enc/acelp_core_enc_fx.c
+++ b/lib_enc/acelp_core_enc_fx.c
@@ -117,6 +117,9 @@ ivas_error acelp_core_enc_fx(
             move16();
             hLPDmem->q_mem_syn = sub( Q_new, 1 );
             move16();
+#ifdef NONBE_FIX_ISSUE_2518
+            st->mem_deemp_preQ_fx = shl_sat( st->mem_deemp_preQ_fx, sub( Q_new, st->prev_Q_new ) );
+#endif
         }
 
         Scale_sig32( st->Bin_E_old_fx, L_FFT / 2, sub( add( Q_new, Q_SCALE - 2 ), st->q_Bin_E_old ) ); // Q_new + Q_scale - 2
@@ -973,6 +976,7 @@ ivas_error acelp_core_enc_fx(
      * Updates
      *-----------------------------------------------------------------*/
 
+#ifndef NONBE_FIX_ISSUE_2518
     IF( st->element_mode > EVS_MONO )
     {
         if ( st->hBWE_TD != NULL )
@@ -983,6 +987,7 @@ ivas_error acelp_core_enc_fx(
         hLPDmem->q_lpd_old_exc = Q_new;
         move16();
     }
+#endif
 
     updt_enc_fx( st, old_exc_fx, pitch_buf, Es_pred_fx, Aq, lsf_new_fx, lsp_new, old_bwe_exc_fx );
 
diff --git a/lib_enc/core_enc_init_fx.c b/lib_enc/core_enc_init_fx.c
index d79a2a3c9d263491ee645326c13280bdbffaf4cd..7efe8a9ff28578122718235c8d76ca5239c7f991 100644
--- a/lib_enc/core_enc_init_fx.c
+++ b/lib_enc/core_enc_init_fx.c
@@ -28,7 +28,11 @@ static void init_tcx_ivas_fx( Encoder_State *st, const Word16 L_frame_old, const
 static void init_core_sig_ana_ivas_fx( Encoder_State *st );
 static void init_modes_ivas_fx( Encoder_State *st, const Word32 last_total_brate );
 static void init_sig_buffers_ivas_fx( Encoder_State *st, const Word16 L_frame_old, const Word16 L_subfr, const Word32 last_total_brate );
+#ifdef NONBE_FIX_ISSUE_2518
+static void init_acelp_ivas_fx( Encoder_State *st, Word16 L_frame_old, const Word32 last_total_brate );
+#else
 static void init_acelp_ivas_fx( Encoder_State *st, Word16 L_frame_old, Word16 shift, const Word32 last_total_brate );
+#endif
 
 /*-----------------------------------------------------------------------*
  * init_coder_ace_plus_fx()
@@ -1085,7 +1089,11 @@ void init_coder_ace_plus_ivas_fx(
 
     /* Initialize ACELP */
 
+#ifdef NONBE_FIX_ISSUE_2518
+    init_acelp_ivas_fx( st, L_frame_old, last_total_brate );
+#else
     init_acelp_ivas_fx( st, L_frame_old, 0, last_total_brate );
+#endif
 
     if ( st->ini_frame == 0 )
     {
@@ -1538,7 +1546,11 @@ static void init_core_sig_ana_ivas_fx( Encoder_State *st )
  *
  *
  *-----------------------------------------------------------------------*/
+#ifdef NONBE_FIX_ISSUE_2518
+static void init_acelp_ivas_fx( Encoder_State *st, Word16 L_frame_old, const Word32 last_total_brate )
+#else
 static void init_acelp_ivas_fx( Encoder_State *st, Word16 L_frame_old, Word16 shift, const Word32 last_total_brate )
+#endif
 {
     Word16 mem_syn_r_size_old;
     Word16 mem_syn_r_size_new;
@@ -1721,8 +1733,13 @@ static void init_acelp_ivas_fx( Encoder_State *st, Word16 L_frame_old, Word16 sh
                     move16();
                     Copy( hLPDmem->mem_syn2, tmp_buf + 1, M );
                     deemph_fx( tmp_buf + 1, st->preemph_fac, M, &tmp );
+#ifdef NONBE_FIX_ISSUE_2518
+                    Residu3_fx( Ap, tmp_buf + M, &tmp, 1, 0 );
+                    hLPDmem->mem_w0 = sub_sat( shl_sat( st->wspeech_enc[-1], sub( hLPDmem->q_mem_syn, sub( Q15, st->exp_buf_wspeech_enc ) ) ), tmp );
+#else
                     Residu3_fx( Ap, tmp_buf + M, &tmp, 1, 1 );
                     hLPDmem->mem_w0 = sub_sat( shr_sat( st->wspeech_enc[-1], shift ), tmp );
+#endif
                     move16();
                 }
             }
diff --git a/lib_enc/core_enc_switch_fx.c b/lib_enc/core_enc_switch_fx.c
index b94595176ae98324ce53fa314f1424ce6a59b05e..3bea33c1228bb5293ae6bd52acca6f1f7c148435 100644
--- a/lib_enc/core_enc_switch_fx.c
+++ b/lib_enc/core_enc_switch_fx.c
@@ -386,6 +386,7 @@ void core_coder_mode_switch_ivas_fx(
         move32();
         st->currEnergyHF_e_fx = 0;
         move16();
+#ifndef NONBE_FIX_ISSUE_2518
         Word16 shift = getScaleFactor16( st->old_inp_16k_fx, L_INP_MEM );
         Scale_sig( st->old_inp_16k_fx, L_INP_MEM, shift );
         st->exp_old_inp_16k = sub( st->exp_old_inp_16k, shift );
@@ -394,12 +395,15 @@ void core_coder_mode_switch_ivas_fx(
         Scale_sig( st->old_inp_12k8_fx, L_INP_MEM, shift );
         st->exp_old_inp_12k8 = sub( st->exp_old_inp_12k8, shift );
         move16();
+#endif
         init_coder_ace_plus_ivas_fx( st, last_total_brate, st->total_brate, MCT_flag );
+#ifndef NONBE_FIX_ISSUE_2518
         if ( st->hLPDmem != NULL )
         {
             st->hLPDmem->q_lpd_old_exc = st->prev_Q_new;
             move16();
         }
+#endif
     }
 
     test();
diff --git a/lib_enc/core_enc_updt_fx.c b/lib_enc/core_enc_updt_fx.c
index f6aba6f612395a6ef00d9b002f6376151556a4af..3272830e8166679fe0ed2934210addacc4c01edc 100644
--- a/lib_enc/core_enc_updt_fx.c
+++ b/lib_enc/core_enc_updt_fx.c
@@ -102,6 +102,7 @@ void core_encode_update_cng_fx(
         p_A += ( M + 1 );
     }
 
+    assert( st->element_mode == EVS_MONO );
     tmp = sub( st->wspeech_enc[-1], shl( hLPDmem->mem_w0, shift ) );
     E_UTIL_deemph2( negate( shift ), wsyn, st->preemph_fac, st->L_frame, &tmp );
     hLPDmem->mem_w0 = sub_sat( st->wspeech_enc[st->L_frame - 1], tmp );
diff --git a/lib_enc/enc_higher_acelp_fx.c b/lib_enc/enc_higher_acelp_fx.c
index 24bf48838bdb9584f095f79c2f889e114930026f..9d74cedc9a0239c1a1ca624a140f485df08b483e 100644
--- a/lib_enc/enc_higher_acelp_fx.c
+++ b/lib_enc/enc_higher_acelp_fx.c
@@ -301,11 +301,26 @@ void transf_cdbk_enc_fx(
      * DCT transform
      *--------------------------------------------------------------*/
 
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+    Word16 q_x_tran;
+    IF( EQ_16( st_fx->element_mode, EVS_MONO ) )
+    {
+        q_x_tran = Q_AVQ_OUT_DEC;
+        move16();
+        Copy_Scale_sig( x_norm, x_tran, Nsv * WIDTH_BAND, q_x_tran );
+    }
+    ELSE
+    {
+        q_x_tran = s_min( Q_AVQ_OUT_DEC, norm_arr( x_norm, Nsv * WIDTH_BAND ) );
+        Copy_Scale_sig_nosat( x_norm, x_tran, Nsv * WIDTH_BAND, q_x_tran );
+    }
+#else
     FOR( i = 0; i < Nsv * WIDTH_BAND; i++ )
     {
         x_tran[i] = shl_sat( x_norm[i], Q_AVQ_OUT_DEC );
         move16();
     }
+#endif
 
     test();
     test();
@@ -321,8 +336,13 @@ void transf_cdbk_enc_fx(
         edct2_fx( L_SUBFR, 1, x_tran, out32, &Qdct, ip_edct2_64, w_edct2_64_fx );
         /*qdct = sub(Q_AVQ_OUT_DEC,qdct+Q_AVQ_OUT_DEC);*/
         Qdct = negate( Qdct );
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        Copy_Scale_sig_32_16( out32, code_preQ, L_SUBFR, Qdct ); /* Output in q_x_tran */
+                                                                 /*qdct = q_x_tran;*/
+#else
         Copy_Scale_sig_32_16( out32, code_preQ, L_SUBFR, Qdct ); /* Output in Q_AVQ_OUT_DEC */
-        /*qdct = Q_AVQ_OUT_DEC;*/
+                                                                 /*qdct = Q_AVQ_OUT_DEC;*/
+#endif
     }
 
     /*--------------------------------------------------------------*
@@ -348,22 +368,41 @@ void transf_cdbk_enc_fx(
     test();
     IF( GT_16( st_fx->element_mode, EVS_MONO ) && NE_16( st_fx->coder_type, INACTIVE ) && GE_32( st_fx->core_brate, MIN_BRATE_AVQ_EXC ) && LE_32( st_fx->core_brate, MAX_BRATE_AVQ_EXC_TD ) && !harm_flag_acelp && code_preQ[0] != 0 )
     {
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        IF( GT_16( abs_s( st_fx->last_code_preq ), shl_sat( abs_s( code_preQ[0] ), sub( Q_AVQ_OUT_DEC + 4, q_x_tran ) ) ) )
+#else
         IF( GT_16( abs_s( st_fx->last_code_preq ), shl_sat( abs_s( code_preQ[0] ), 4 ) ) )
+#endif
         {
             st_fx->mem_preemp_preQ_fx = shr( st_fx->mem_preemp_preQ_fx, 4 );
             move16();
         }
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        ELSE IF( GT_16( abs_s( st_fx->last_code_preq ), shl_sat( abs_s( code_preQ[0] ), sub( Q_AVQ_OUT_DEC + 3, q_x_tran ) ) ) )
+#else
         ELSE IF( GT_16( abs_s( st_fx->last_code_preq ), shl_sat( abs_s( code_preQ[0] ), 3 ) ) )
+#endif
         {
             st_fx->mem_preemp_preQ_fx = shr( st_fx->mem_preemp_preQ_fx, 3 );
             move16();
         }
     }
 
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+    st_fx->last_code_preq = shl_sat( code_preQ[L_SUBFR - 1], sub( 1, q_x_tran ) ); // Q0 ? Q1
+    move16();
+
+    st_fx->mem_preemp_preQ_fx = shl_sat( st_fx->mem_preemp_preQ_fx, sub( q_x_tran, Q_AVQ_OUT_DEC ) );
+    move16();
+    preemph_fx( code_preQ, FAC_PRE_AVQ_FX, L_SUBFR, &( st_fx->mem_preemp_preQ_fx ) );
+    st_fx->mem_preemp_preQ_fx = shl_sat( st_fx->mem_preemp_preQ_fx, sub( Q_AVQ_OUT_DEC, q_x_tran ) );
+    move16();
+#else
     st_fx->last_code_preq = shr( code_preQ[L_SUBFR - 1], 9 ); // Q0
     move16();
 
     preemph_fx( code_preQ, FAC_PRE_AVQ_FX, L_SUBFR, &( st_fx->mem_preemp_preQ_fx ) );
+#endif
 
     /*--------------------------------------------------------------*
      * For inactive segments
@@ -376,22 +415,36 @@ void transf_cdbk_enc_fx(
     IF( EQ_16( st_fx->coder_type, INACTIVE ) )
     {
         /*ftemp = fcode_preQ[0] *fh1[L_SUBFR-1];*/
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        Ltmp = L_mult( code_preQ[0], h1[L_SUBFR - 1] ); /*1+14+shift + q_x_tran */
+#else
         Ltmp = L_mult( code_preQ[0], h1[L_SUBFR - 1] ); /*1+14+shift + Q_AVQ_OUT */
+#endif
         FOR( i = 1; i < L_SUBFR; i++ )
         {
             /*ftemp += fcode_preQ[i] * fh1[L_SUBFR-1-i];*/
             Ltmp = L_mac( Ltmp, code_preQ[i], h1[L_SUBFR - 1 - i] );
         }
         /*fxn[L_SUBFR-1] -= *fgain_preQ * ftemp;*/
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        Ltmp = L_shr( Mult_32_16( Ltmp, *gain_preQ ), sub( add( q_x_tran, 2 ), Q_new ) ); /* (2 + 1 + 14 +shift+Q_AVQ_OUT)-(Q_AVQ_OUT+2-Q_new) = 15 + Q_new + shift */
+#else
         Ltmp = L_shr( Mult_32_16( Ltmp, *gain_preQ ), sub( add( Q_AVQ_OUT_DEC, 2 ), Q_new ) ); /* (2 + 1 + 14 +shift+Q_AVQ_OUT)-(Q_AVQ_OUT+2-Q_new) = 15 + Q_new + shift */
-        xn[L_SUBFR - 1] = round_fx( L_sub( L_mult( xn[L_SUBFR - 1], 32767 ), Ltmp ) );         /* -> Q_new + shift -1 */
+#endif
+        xn[L_SUBFR - 1] = round_fx( L_sub( L_mult( xn[L_SUBFR - 1], 32767 ), Ltmp ) ); /* -> Q_new + shift -1 */
     }
     ELSE
     {
         conv_fx( code_preQ, h1, x_tran, L_SUBFR );
+#ifdef NONBE_FIX_ISSUE_2518_TRANSENC_SAT_FIX
+        updt_tar_HR_fx( cn, cn, code_preQ, *gain_preQ, sub( Q_new, add( -15 + 2, q_x_tran ) ), L_SUBFR );
+
+        updt_tar_HR_fx( xn, xn, x_tran, *gain_preQ, sub( Q_new, add( -15 + 2, q_x_tran ) ), L_SUBFR );
+#else
         updt_tar_HR_fx( cn, cn, code_preQ, *gain_preQ, sub( Q_new, add( -15 + 2, Q_AVQ_OUT_DEC ) ), L_SUBFR );
 
         updt_tar_HR_fx( xn, xn, x_tran, *gain_preQ, sub( Q_new, add( -15 + 2, Q_AVQ_OUT_DEC ) ), L_SUBFR );
+#endif
         *gain_pit = corr_xy1_fx( xn, y1, g_corr, L_SUBFR, 0, &Overflow ); /* Q14 */
         move16();
         /* clip gain if necessary to avoid problems at decoder */
diff --git a/lib_enc/init_enc_fx.c b/lib_enc/init_enc_fx.c
index e47b7621f600edcb7e015104284d1027875515ef..60760e2fb95cf291a1a0553e5c7633b1421a077a 100644
--- a/lib_enc/init_enc_fx.c
+++ b/lib_enc/init_enc_fx.c
@@ -249,6 +249,13 @@ ivas_error init_encoder_fx(
 
     st->prev_Q_new = 0;
     move16();
+#ifdef NONBE_FIX_ISSUE_2518
+    if ( st->element_mode > EVS_MONO )
+    {
+        st->prev_Q_new = Q15;
+        move16();
+    }
+#endif
 
     IF( EQ_32( st->input_Fs, 8000 ) )
     {
@@ -1144,11 +1151,13 @@ ivas_error init_encoder_fx(
         init_coder_ace_plus_ivas_fx( st, st->last_total_brate, igf_brate, 0 );
     }
 
+#ifndef NONBE_FIX_ISSUE_2518
     IF( st->hLPDmem != NULL )
     {
         st->hLPDmem->q_lpd_old_exc = st->prev_Q_new;
         move16();
     }
+#endif
 
     /*-----------------------------------------------------------------*
      * FD-CNG encoder
diff --git a/lib_enc/ivas_core_enc_fx.c b/lib_enc/ivas_core_enc_fx.c
index 6b8f647e5c34d538fcfe5b95837a7bc552712bdb..b734fce5223b569dbb8e7f4934e0004a8d112ed3 100644
--- a/lib_enc/ivas_core_enc_fx.c
+++ b/lib_enc/ivas_core_enc_fx.c
@@ -452,11 +452,13 @@ ivas_error ivas_core_enc_fx(
 #ifndef NONBE_FIX_ISSUE_2206_MDCT_STEREO_FIX_2549
                     Scale_sig( old_inp_16k_fx[n], L_INP, sub( Q1, Q_new[n] ) ); // Q0
 #endif
+#ifndef NONBE_FIX_ISSUE_2518
                     IF( NE_16( st->element_mode, IVAS_CPE_DFT ) && NE_16( st->element_mode, IVAS_CPE_MDCT ) )
                     {
                         st->hTcxEnc->exp_buf_speech_ltp = st->exp_buf_speech_enc;
                         move16();
                     }
+#endif
                 }
                 Word16 Q_spec_old[2], L_spec;
 #endif
@@ -582,12 +584,14 @@ ivas_error ivas_core_enc_fx(
                     Scale_sig( old_inp_16k_fx[i], L_INP, sub( Q1, Q_new[i] ) ); // Q0
 #endif
 
+#ifndef NONBE_FIX_ISSUE_2518
                     test();
                     IF( NE_16( st->element_mode, IVAS_CPE_DFT ) && NE_16( st->element_mode, IVAS_CPE_MDCT ) )
                     {
                         st->hTcxEnc->exp_buf_speech_ltp = st->exp_buf_speech_enc;
                         move16();
                     }
+#endif
                     shift = norm_arr( st->input_fx, input_frame );
 #ifdef NONBE_FIX_ISSUE_2206
                     Q_min = add( st->q_inp, shift );
diff --git a/lib_enc/ivas_core_pre_proc_front_fx.c b/lib_enc/ivas_core_pre_proc_front_fx.c
index 6c9d56fe00df90bff37035853da975202063ca19..77be7fe6ddeffe3b78136ebc404aa9a0beaa302b 100644
--- a/lib_enc/ivas_core_pre_proc_front_fx.c
+++ b/lib_enc/ivas_core_pre_proc_front_fx.c
@@ -211,9 +211,15 @@ void pre_proc_front_ivas_fx(
     Word16 sf_energySum[CLDFB_NO_CHANNELS_MAX];
     Word16 Q_inp_const = -1;
     move16();
+#ifdef NONBE_FIX_ISSUE_2518
+    Word16 preemp_len;
+    Word16 *preemp_start_idx = NULL;
+    Word32 sig_out[STEREO_DFT_OVL_16k + L_FRAME16k /* = max( L_FRAME16k + STEREO_DFT_OVL_16k, L_FRAME16k + L_FILT16k + lMemRecalc_16k ) */];
+#else
     Word16 headroom, preemp_len, inp_max;
     Word16 *preemp_start_idx = NULL;
     Word32 sig_out[STEREO_DFT_OVL_16k + L_FRAME16k /* = max( L_FRAME16k + STEREO_DFT_OVL_16k, L_FRAME16k + L_FILT16k + lMemRecalc_16k ) */], max_32;
+#endif
 
     push_wmops( "pre_proc_front" );
     /*------------------------------------------------------------------*
@@ -572,9 +578,15 @@ void pre_proc_front_ivas_fx(
 #endif
     }
 #ifdef NONBE_FIX_ISSUE_2206
+#ifdef NONBE_FIX_ISSUE_2518
+    st->q_mem_decim_fx = add( st->q_inp, norm_arr( st->mem_decim_fx_q_inp, 2 * L_FILT_MAX ) );
+    move16();
+    Copy_Scale_sig_nosat( st->mem_decim_fx_q_inp, st->mem_decim_fx, 2 * L_FILT_MAX, sub( st->q_mem_decim_fx, st->q_inp ) );
+#else
     Copy( st->mem_decim_fx_q_inp, st->mem_decim_fx, 2 * L_FILT_MAX );
     st->q_mem_decim_fx = st->q_inp;
     move16();
+#endif
 
     Word16 q_buf_speech_enc;
 
@@ -627,6 +639,7 @@ void pre_proc_front_ivas_fx(
      * Perform fixed preemphasis (12.8 kHz signal) through 1 - g*z^-1
      *-----------------------------------------------------------------*/
 
+#ifndef NONBE_FIX_ISSUE_2518
 #ifdef NONBE_FIX_ISSUE_2206
     headroom = 0;
     move16();
@@ -638,6 +651,7 @@ void pre_proc_front_ivas_fx(
 #else
     headroom = 2;
     move16();
+#endif
 #endif
     preemp_len = 0;
     move16();
@@ -734,6 +748,26 @@ void pre_proc_front_ivas_fx(
     move16();
     st->mem_preemph_q = st->q_inp;
     move16();
+#ifdef NONBE_FIX_ISSUE_2518
+    Word16 shift = L_norm_arr( sig_out, preemp_len );
+    shift = s_min( shift, norm_arr( old_inp_12k8_fx, (Word16) ( preemp_start_idx - old_inp_12k8_fx ) ) );
+    shift = add( shift, st->q_inp );
+
+    /* Avoid saturation of resampling/delay decimation buffer. */
+    shift = s_min( shift, st->q_mem_decim16k_fx );
+
+    /* Limit Q_new here to st->q_inp because inside ivas_compute_core_buffers_fx() st->input is rescaled to Q_new */
+    shift = s_min( shift, st->q_inp );
+    IF( st->hLPDmem != NULL )
+    {
+        shift = s_min( shift, st->hLPDmem->q_lpd_old_exc );
+        shift = s_min( shift, st->hLPDmem->q_lpd_syn );
+        shift = s_min( shift, add( st->hLPDmem->q_mem_syn, 1 ) );
+    }
+
+    *Q_new = s_min( shift, Q_MAX );
+    move16();
+#else
     maximum_abs_32_fx( sig_out, preemp_len, &max_32 );
     inp_max = s_max( extract_h( max_32 ), 1 );
 
@@ -769,7 +803,9 @@ void pre_proc_front_ivas_fx(
     st->Q_max[i] = shift;
     move16();
 #endif
+#endif
 
+#ifndef NONBE_FIX_ISSUE_2518
 #ifdef NONBE_FIX_ISSUE_2206
     /* Avoid saturation of resampling decimation buffer inside ivas_compute_core_buffers_fx(). */
     *Q_new = s_min( *Q_new, st->q_mem_decim16k_fx );
@@ -778,6 +814,7 @@ void pre_proc_front_ivas_fx(
 #endif
     *Q_new = add( *Q_new, Q_inp_const );
     move16();
+#endif
     Copy_Scale_sig32_16( sig_out, preemp_start_idx, preemp_len, sub( add( *Q_new, 1 ), st->q_inp ) );        /* Q_new */
     Scale_sig( old_inp_12k8_fx, (Word16) ( preemp_start_idx - old_inp_12k8_fx ), sub( *Q_new, st->q_inp ) ); /* Q_new */
 #ifdef NONBE_FIX_ISSUE_2206
diff --git a/lib_enc/ivas_core_pre_proc_fx.c b/lib_enc/ivas_core_pre_proc_fx.c
index 6f95331cc3bc11efdda01ec153eb61746ad4785d..22bf0522bd20212f4721d7bfa553ac6927b1f5b8 100644
--- a/lib_enc/ivas_core_pre_proc_fx.c
+++ b/lib_enc/ivas_core_pre_proc_fx.c
@@ -831,9 +831,15 @@ void ivas_compute_core_buffers_fx(
 #else
     Word16 i, shift, Q_min;
 #endif
+#ifdef NONBE_FIX_ISSUE_2518
+    Word16 preemp_len;
+    Word16 *preemp_start_idx = NULL;
+    Word32 sig_out[STEREO_DFT_OVL_16k + L_FRAME16k + L_FILT16k];
+#else
     Word16 preemp_len, inp_max;
     Word16 *preemp_start_idx = NULL;
     Word32 sig_out[STEREO_DFT_OVL_16k + L_FRAME16k + L_FILT16k], max_32;
+#endif
 
 #ifdef NONBE_FIX_ISSUE_2206
     assert( Q_old_inp_16k == ( *Q_new - 1 ) );
@@ -961,7 +967,6 @@ void ivas_compute_core_buffers_fx(
             size_modified = modify_Fs_fx( temp1F_icatdmResampBuf_fx, NS2SA_FX2( input_Fs, DELAY_FIR_RESAMPL_NS ), input_Fs, new_inp_16k_fx + NS2SA_FX2( sr_core, FRAME_SIZE_NS ), sr_core, mem_decim16k_dummy_fx, 0, &Q_tmp, &mem_decim16k_size ); /* Q0 */
 #ifdef NONBE_FIX_ISSUE_2206
             scale_sig( new_inp_16k_fx + NS2SA_FX2( sr_core, FRAME_SIZE_NS ), size_modified, negate( Q_tmp ) ); /* scaling back to Q_old_inp_16k */
-            // Scale_sig( st->mem_decim16k_fx, 2 * L_FILT_MAX, sub( -1, Q_old_inp_16k ) ); /* Q(-1) */
             Q_tmp = norm_arr( st->mem_decim16k_fx, mem_decim16k_size );
             scale_sig( st->mem_decim16k_fx, mem_decim16k_size, Q_tmp );
             st->q_mem_decim16k_fx = add( Q_tmp, Q_old_inp_16k );
@@ -1314,6 +1319,23 @@ void ivas_compute_core_buffers_fx(
             preemp_len = L_FRAME16k + L_FILT16k;
             move16();
         }
+#ifdef NONBE_FIX_ISSUE_2518
+        shift = L_norm_arr( sig_out, preemp_len );
+        shift = s_min( shift, norm_arr( old_inp_16k_fx, (Word16) ( preemp_start_idx - old_inp_16k_fx ) ) );
+        shift = add( shift, Q_old_inp_16k );
+
+        /* Avoid saturation of resampling/delay decimation buffer. */
+        shift = s_min( shift, add( st->q_mem_decim16k_fx, 1 ) );
+
+        IF( st->hLPDmem != NULL )
+        {
+            shift = s_min( shift, st->hLPDmem->q_lpd_old_exc );
+            shift = s_min( shift, st->hLPDmem->q_lpd_syn );
+            shift = s_min( shift, add( st->hLPDmem->q_mem_syn, 1 ) );
+        }
+        *Q_new = s_min( shift, Q_MAX );
+        move16();
+#else
         maximum_abs_32_fx( sig_out, preemp_len, &max_32 );
         inp_max = s_max( extract_h( max_32 ), 1 );
 
@@ -1323,6 +1345,7 @@ void ivas_compute_core_buffers_fx(
 #else
         shift = sub( norm_s( inp_max ), 1 /* headroom */ );
 #endif
+
 #ifdef NONBE_FIX_ISSUE_2206
         *Q_new = s_min( shift, Q_MAX );
         move16();
@@ -1353,6 +1376,7 @@ void ivas_compute_core_buffers_fx(
         st->Q_max_16k[i] = shift;
         move16();
 #endif
+#endif
 
 #ifndef NONBE_FIX_ISSUE_2206
         Copy_Scale_sig32_16( sig_out, preemp_start_idx, preemp_len, add( *Q_new, 1 ) );
diff --git a/lib_enc/stat_enc.h b/lib_enc/stat_enc.h
index f84b518245749b39889e90a05a467a075887a2d5..862292de802b6e7ce0b1c5b68a1b1f2192f2a79a 100644
--- a/lib_enc/stat_enc.h
+++ b/lib_enc/stat_enc.h
@@ -1790,7 +1790,9 @@ typedef struct enc_core_structure
      * Fixed point only variables
      *----------------------------------------------------------------------------------*/
 
+#ifndef NONBE_FIX_ISSUE_2518
     Word16 Q_exc;
+#endif
     Word16 Q_stat_noise_ge;
     Word16 Q_stat_noise;
     Word16 Q_syn2;
diff --git a/lib_enc/updt_enc_fx.c b/lib_enc/updt_enc_fx.c
index 65f997c63b029eb47fbd593750dbd44414bbd7d2..9224b1081343fb5b130dae255ec461b4ddb0670d 100644
--- a/lib_enc/updt_enc_fx.c
+++ b/lib_enc/updt_enc_fx.c
@@ -34,8 +34,47 @@ void updt_enc_fx(
     GSC_ENC_HANDLE hGSCEnc = st->hGSCEnc;
     TD_BWE_ENC_HANDLE hBWE_TD = st->hBWE_TD;
 
+#ifdef NONBE_FIX_ISSUE_2518
+    /* update old excitation buffer */
+    IF( st->element_mode > EVS_MONO )
+    {
+        tmp = norm_arr( &old_exc[st->L_frame], L_EXC_MEM );
+        tmp = s_min( tmp, sub( 15, hLPDmem->q_lpd_old_exc ) );
+        Copy_Scale_sig_nosat( &old_exc[st->L_frame], hLPDmem->old_exc, L_EXC_MEM, tmp );
+        hLPDmem->q_lpd_old_exc = add( hLPDmem->q_lpd_old_exc, tmp );
+        move16();
+
+        tmp = norm_arr( st->hLPDmem->syn, M + 1 );
+        tmp = s_min( tmp, sub( 15, hLPDmem->q_lpd_syn ) );
+        scale_sig( st->hLPDmem->syn, M, tmp );
+        st->hLPDmem->q_lpd_syn = add( st->hLPDmem->q_lpd_syn, tmp );
+        move16();
+
+        tmp = norm_arr( hLPDmem->mem_syn, M );
+        tmp = s_min( tmp, norm_arr( hLPDmem->mem_syn1_fx, M ) );
+        tmp = s_min( tmp, norm_arr( hLPDmem->mem_syn2, M ) );
+        tmp = s_min( tmp, norm_arr( hLPDmem->mem_syn3, M ) );
+        tmp = s_min( tmp, norm_arr( hLPDmem->mem_syn_r, L_SYN_MEM ) );
+        tmp = s_min( tmp, norm_s( hLPDmem->mem_w0 ) );
+        tmp = s_min( tmp, sub( 15, hLPDmem->q_mem_syn ) );
+        // tmp = sub( tmp, 1 );
+        scale_sig( hLPDmem->mem_syn, M, tmp );
+        scale_sig( hLPDmem->mem_syn1_fx, M, tmp );
+        scale_sig( hLPDmem->mem_syn2, M, tmp );
+        scale_sig( hLPDmem->mem_syn3, M, tmp );
+        scale_sig( hLPDmem->mem_syn_r, L_SYN_MEM, tmp );
+        hLPDmem->mem_w0 = shl( hLPDmem->mem_w0, tmp );
+        move16();
+        st->hLPDmem->q_mem_syn = add( st->hLPDmem->q_mem_syn, tmp );
+    }
+    ELSE
+    {
+        Copy( &old_exc[st->L_frame], hLPDmem->old_exc, L_EXC_MEM );
+    }
+#else
     /* update old excitation buffer */
     Copy( &old_exc[st->L_frame], hLPDmem->old_exc, L_EXC_MEM );
+#endif
     test();
     test();
     IF( !st->Opt_AMR_WB && st->hBWE_TD != NULL )