diff --git a/lib_com/options.h b/lib_com/options.h
index 9b03463a181acdc36ccd7594187aac3a70b3d32e..47398d087edd01542924b0297b1956fa70f684bb 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -144,7 +144,7 @@
 /* ################### Start FIXES switches ########################### */
 
 #define NONBE_FIX_864_JBM_RENDER_FRAMESIZE                    /* FhG: issue #864: fix different behaviour of JBM TSM with different render frame sizes */
-
+#define NONBE_FIX_TCX5_INTERLEAVING_FOR_FS_IN_UNEQUAL_FS_OUT  /* FhG: apply correct TCX5 grouping/interleaving when input_fs != output_fs */
 
 /* #################### End FIXES switches ############################ */
 
diff --git a/lib_dec/dec_tcx.c b/lib_dec/dec_tcx.c
index f68ba522bb0f2bab761e3d9abb5f2cddf46e8d17..fbe24112827c066ce6d1fa1de4e7d37eb8e21940 100644
--- a/lib_dec/dec_tcx.c
+++ b/lib_dec/dec_tcx.c
@@ -1501,7 +1501,11 @@ void decoder_tcx_tns(
             hTcxCfg->tcx_last_overlap_mode = hTcxCfg->tcx_curr_overlap_mode;
         }
 
+#ifdef NONBE_FIX_TCX5_INTERLEAVING_FOR_FS_IN_UNEQUAL_FS_OUT
+        if ( ( hTcxCfg->fIsTNSAllowed && fUseTns != 0 && bfi != 1 && whitenedDomain ) || ( L_spec > L_frameTCX ) )
+#else
         if ( ( hTcxCfg->fIsTNSAllowed && fUseTns != 0 && bfi != 1 ) || ( L_spec > L_frameTCX ) )
+#endif
         {
             L = L_spec;
         }
@@ -1543,7 +1547,12 @@ void decoder_tcx_tns(
 
         if ( ( L_frame == st->L_frame >> 1 ) && st->tcxonly && isTCX5 )
         {
+
+#ifdef NONBE_FIX_TCX5_INTERLEAVING_FOR_FS_IN_UNEQUAL_FS_OUT
+            if ( st->element_mode == EVS_MONO || ( L_spec < L_frameTCX && !whitenedDomain ) ) /* todo: this is temporary to maintain EVS BE, this is a bug and should be fixed also for EVS (see issue 13) */
+#else
             if ( st->element_mode == EVS_MONO || L_spec < L_frameTCX ) /* todo: this is temporary to maintain EVS BE, this is a bug and should be fixed also for EVS (see issue 13) */
+#endif
             {
                 tcx5TnsUngrouping( L_frameTCX >> 1, hTcxCfg->tnsConfig[0][0].iFilterBorders[0] >> 1, x, DEC );
             }