diff --git a/lib_com/options.h b/lib_com/options.h
index 7517ca330dfda4f60667976f4f48de804f8e2f90..320b1cedac5bd23e6f53911fff437ef2fabf5f99 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -109,6 +109,7 @@
 #define OPT_TCXLTP_FILTER_LOOP                               /* FhG: optimize loop in tcx_ltp_synth_filter */
 #define FIX_2049_DIFF_IN_DECORR_TAIL                         /* FhG: correct scale values in ivas_dirac_dec_binaural_process_output_fx() */
 #define FIX_2602_NONBE_SAT_IN_SWB_TBE_SCALE                  /* Dolby/FhG: fix for issue 2026: Saturation in SWB TBE re-scaling function preventing StereoDownmix complexity job to complete */
+#define FIX_2021_BANDWIDTH_EXTENSION_PROBLEM                 /* FhG: increase cldfb buffer precision*/
 
 /* #################### Start BASOP porting switches ############################ */
 
diff --git a/lib_enc/ivas_core_enc_fx.c b/lib_enc/ivas_core_enc_fx.c
index 2c23205d0951577bf2982855c9ba31480fbd0712..c296c816c8a6eb9c3d33cbc8b4c7a87e8288a15e 100644
--- a/lib_enc/ivas_core_enc_fx.c
+++ b/lib_enc/ivas_core_enc_fx.c
@@ -697,12 +697,40 @@ ivas_error ivas_core_enc_fx(
         {
             /* Common pre-processing for SWB(FB) TBE and SWB(FB) BWE */
             /* Scaling cldfb_state_fx */
+#ifdef FIX_2021_BANDWIDTH_EXTENSION_PROBLEM
+            Word16 q_shift, scf_cldfb;
+            scf_cldfb = L_norm_arr( st->cldfbSynTd->cldfb_state_fx, st->cldfbSynTd->p_filter_length );
+
+            scale_sig32( st->cldfbSynTd->cldfb_state_fx, st->cldfbSynTd->p_filter_length, scf_cldfb );
+            st->cldfbSynTd->Q_cldfb_state = add( st->cldfbSynTd->Q_cldfb_state, scf_cldfb );
+
+            q_shift = sub( sub( q_re_im_buf[n], 1 ), st->cldfbSynTd->Q_cldfb_state ); // cldfb_state_fx will be used in cldfbSynthesis_ivas_fx and has to be aligned with (q_re_im_buf[n] - 1)
+            IF( GT_32( q_shift, 0 ) )
+            {
+                FOR( int ts = 0; ts < CLDFB_NO_COL_MAX; i++ )
+                {
+                    scale_sig32( realBuffer_fx[n][ts], CLDFB_NO_CHANNELS_MAX, negate( q_shift ) );
+                    scale_sig32( imagBuffer_fx[n][ts], CLDFB_NO_CHANNELS_MAX, negate( q_shift ) );
+                }
+                q_re_im_buf[n] = add( st->cldfbSynTd->Q_cldfb_state, 1 );
+            }
+            ELSE
+            {
+                scale_sig32( st->cldfbSynTd->cldfb_state_fx, st->cldfbSynTd->p_filter_length, q_shift ); // st->cldfbSynTd->Q_cldfb_state -> q_realImagBuffer
+                st->cldfbSynTd->Q_cldfb_state = sub( q_re_im_buf[n], 1 );
+            }
+#else
             scale_sig32( st->cldfbSynTd->cldfb_state_fx, st->cldfbSynTd->p_filter_length, sub( q_re_im_buf[n], st->cldfbSynTd->Q_cldfb_state ) ); // st->cldfbSynTd->Q_cldfb_state -> q_realImagBuffer
+#endif
 
             swb_pre_proc_ivas_fx( st, new_swb_speech_fx_16, new_swb_speech_fx, shb_speech_fx, &Q_shb_spch, realBuffer_fx[n], imagBuffer_fx[n], q_re_im_buf[n], hCPE );
 
+#ifdef FIX_2021_BANDWIDTH_EXTENSION_PROBLEM
+            st->cldfbSynTd->Q_cldfb_state = sub( q_re_im_buf[n], 1 );
+#else
             /* Re-scaling cldfb_state_fx */
             scale_sig32( st->cldfbSynTd->cldfb_state_fx, st->cldfbSynTd->p_filter_length, negate( sub( q_re_im_buf[n], st->cldfbSynTd->Q_cldfb_state ) ) ); // q_realImagBuffer -> st->cldfbSynTd->Q_cldfb_state
+#endif
         }
         ELSE IF( GE_32( input_Fs, 32000 ) )
         {
diff --git a/lib_enc/swb_pre_proc_fx.c b/lib_enc/swb_pre_proc_fx.c
index 2cd295acd7f43512eed3a204067af7a6d8be04fb..f857cbec0b2daa6e0c1894b271f2b9a3c70134be 100644
--- a/lib_enc/swb_pre_proc_fx.c
+++ b/lib_enc/swb_pre_proc_fx.c
@@ -1104,6 +1104,10 @@ void swb_pre_proc_ivas_fx(
     IF( ( ( st->core == ACELP_CORE ) && NE_16( st->extl, SWB_BWE_HIGHRATE ) && NE_16( st->extl, FB_BWE_HIGHRATE ) ) ||
         ( ( EQ_32( st->total_brate, ACELP_9k60 ) || st->rf_mode ) && EQ_16( st->bwidth, SWB ) && ( st->element_mode == EVS_MONO ) ) )
     {
+#ifdef FIX_2021_BANDWIDTH_EXTENSION_PROBLEM
+        Word64 CldfbHB64_fx = 0;
+        move64();
+#endif
         Word32 CldfbHB_fx = 0;   // fixed counterpart
         Word16 CldfbHB_fx_e = 0; // fixed counterpart
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
@@ -1214,16 +1218,28 @@ void swb_pre_proc_ivas_fx(
             {
                 FOR( ts = 0; ts < CLDFB_NO_COL_MAX; ts++ )
                 {
+#ifdef FIX_2021_BANDWIDTH_EXTENSION_PROBLEM
+                    CldfbHB64_fx = W_mac_32_32( CldfbHB64_fx, realBufferFlipped[ts][nB], realBufferFlipped[ts][nB] );
+                    CldfbHB64_fx = W_mac_32_32( CldfbHB64_fx, imagBufferFlipped[ts][nB], imagBufferFlipped[ts][nB] );
+#else
                     realQ_neg1 = extract_l( L_shr( realBufferFlipped[ts][nB], 16 ) );
                     imagQ_neg1 = extract_l( L_shr( imagBufferFlipped[ts][nB], 16 ) ); /* Q(-1), headroom needed */
 
                     CldfbHB_fx = L_mac0_o( CldfbHB_fx, realQ_neg1, realQ_neg1, &Overflow );
                     CldfbHB_fx = L_mac0_o( CldfbHB_fx, imagQ_neg1, imagQ_neg1, &Overflow ); /* Q(-2) */
+#endif
                 }
             }
+#ifdef FIX_2021_BANDWIDTH_EXTENSION_PROBLEM
+            Word16 scf = W_norm( CldfbHB64_fx );
+            CldfbHB64_fx = W_shl( CldfbHB64_fx, scf );
+            CldfbHB_fx = W_extract_h( CldfbHB64_fx );
+            CldfbHB_fx_e = sub( Q31, add( shl( q_reImBuffer, 1 ), sub( scf, Q31 ) ) );
+#else
             CldfbHB_fx_e = sub( Q31, shl( sub( q_reImBuffer, Q16 ), 1 ) );
             exp = norm_l( CldfbHB_fx );
-            CldfbHB_fx = L_shl( CldfbHB_fx, exp );   /* CldfbHB_ener = CldfbHB_fl*2^(exp) */
+            CldfbHB_fx = L_shl( CldfbHB_fx, exp ); /* CldfbHB_ener = CldfbHB_fl*2^(exp) */
+#endif
             Cldfbtemp1 = Log2_norm_lc( CldfbHB_fx ); /* Log2_norm_lc(t) = 2^15*(log2(t/2^30)) */
             Cldfbtemp1 = sub( shr( Cldfbtemp1, 6 ), shl( add( sub( Q31 - Q30, CldfbHB_fx_e ), exp ), 9 ) );
             CldfbHB_fx = L_mult( Cldfbtemp1, 9864 ); /* Q9 + Q15 + Q1 = Q25 */