diff --git a/lib_com/options.h b/lib_com/options.h
index f73c6155bad7fee9b04186c7215743279192d4ef..863f6c36905521ba512fcb2b831e60164c283a22 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -207,9 +207,12 @@
 #define FIX_983_DISC_ISM_DIGEST_NUM_OBJS                /* FhG: issue #983: the discrete ISM digest function uses the wrong number of objects */
 #define FIX_966_VAR_OVERFLOW_IN_HARM_MODEL_ARI          /* FhG: fix and undef behaviour bug in the harmonic TCX model arithmetic coder */
 #define NONBE_FIX_974_OSBA_JBM_MONO_RS_USAN             /* FhG : issue #974: usan in mono and stereo output in OSBA JBM RS */
-#define NONBE_FIX_982_OMASA_DELAY_COMP_5MS               /* FhG : issue #982 : 5ms and 20ms output different for OMASA */
+#define NONBE_FIX_982_OMASA_DELAY_COMP_5MS              /* FhG : issue #982 : 5ms and 20ms output different for OMASA */
 #define NONBE_FIX_975_JBM_USAN                          /* FhG: Fix issue #975, USAN in JBM decoding ad 13.2kbps */
 
+#define FIX_ACCESS_WITHIN_NULL_STRUCT_MC_BW_SWITCHING   /* FhG: fix usan error in MCT with bw swicthing */
+#define NONBE_FIX_986_MC_BW_SWITCHING                   /* FhG: fix crash in bw and br switching with MC */
+
 /* #################### End BASOP porting switches ############################ */
 
 /* clang-format on */
diff --git a/lib_enc/bw_detect.c b/lib_enc/bw_detect.c
index 75a97feafbc664d7d44e5e60eb43a3e0aaa20d68..cd26afb12e6bcd6674aee898046d700a5e6ab3fc 100644
--- a/lib_enc/bw_detect.c
+++ b/lib_enc/bw_detect.c
@@ -713,6 +713,26 @@ int16_t set_bw_mct(
     }
 
     bw_changed = 0;
+#ifdef NONBE_FIX_986_MC_BW_SWITCHING
+    if ( mct_bwidth != last_mct_bwidth )
+    {
+        bw_changed = 1;
+    }
+
+    /*
+     * always set bw for all CPEs even if it is the same value as before,
+     * in case of bw + br switching when changing to MCT, this overwrites
+     * potentially incorrect initial values
+     */
+    for ( cpe_id = 0; cpe_id < nCPE; cpe_id++ )
+    {
+        for ( ch = 0; ch < CPE_CHANNELS; ch++ )
+        {
+            st = hCPE[cpe_id]->hCoreCoder[ch];
+            st->bwidth = mct_bwidth;
+        }
+    }
+#else
     if ( mct_bwidth != last_mct_bwidth )
     {
         bw_changed = 1;
@@ -726,6 +746,7 @@ int16_t set_bw_mct(
             }
         }
     }
+#endif
 
     return bw_changed;
 }
diff --git a/lib_enc/ivas_cpe_enc.c b/lib_enc/ivas_cpe_enc.c
index 9edcf9a27441e367a948aabc3fcd000e23a65eb4..5b74cec0c42f846233dc904d0030ccc8f0b32f73 100644
--- a/lib_enc/ivas_cpe_enc.c
+++ b/lib_enc/ivas_cpe_enc.c
@@ -578,7 +578,15 @@ ivas_error ivas_cpe_enc(
         if ( ( hCPE->last_element_brate != hCPE->element_brate || hCPE->element_mode != hCPE->last_element_mode || ( hCPE->element_mode == IVAS_CPE_TD && sts[0]->bits_frame_nominal != last_bits_frame_nominal ) || sts[n]->last_bwidth != sts[n]->bwidth ) && ( n == 0 || hCPE->element_mode == IVAS_CPE_MDCT ) )
         {
             int16_t igf;
+
+#ifdef NONBE_FIX_986_MC_BW_SWITCHING
+            int16_t bw;
+
+            bw = ( hCPE->element_mode == IVAS_CPE_MDCT ) ? sts[n]->bwidth : sts[n]->max_bwidth;
+            igf = getIgfPresent( sts[n]->element_mode, sts[n]->bits_frame_nominal * FRAMES_PER_SEC, bw, sts[n]->rf_mode );
+#else
             igf = getIgfPresent( sts[n]->element_mode, sts[n]->bits_frame_nominal * FRAMES_PER_SEC, sts[n]->max_bwidth, sts[n]->rf_mode );
+#endif
             if ( ( error = IGF_Reconfig( &sts[n]->hIGFEnc, igf, 0, sts[n]->bits_frame_nominal * FRAMES_PER_SEC, sts[n]->max_bwidth, sts[n]->element_mode, sts[n]->rf_mode ) ) != IVAS_ERR_OK )
             {
                 return error;
diff --git a/lib_enc/ivas_mct_core_enc.c b/lib_enc/ivas_mct_core_enc.c
index 3c345b472d32e3c6c6341a3e8e61f5031bfa4ae3..6146378f43719c80721034eb3d82b254f0f2a676 100644
--- a/lib_enc/ivas_mct_core_enc.c
+++ b/lib_enc/ivas_mct_core_enc.c
@@ -279,8 +279,14 @@ void ivas_mct_core_enc(
 
         if ( switch_bw )
         {
-            initMdctStereoEncData( hMCT->hBlockData[ch]->hStereoMdct, ivas_format, sts[ch_core]->element_mode, sts[ch_core]->element_brate, sts[ch_core]->bwidth,
-                                   sts[ch_core]->igf, sts[ch_core]->hIGFEnc->igfData.igfInfo.grid, 0 );
+#ifdef FIX_ACCESS_WITHIN_NULL_STRUCT_MC_BW_SWITCHING
+            H_IGF_GRID igf_grid;
+
+            igf_grid = sts[ch_core]->igf ? sts[ch_core]->hIGFEnc->igfData.igfInfo.grid : NULL;
+            initMdctStereoEncData( hMCT->hBlockData[ch]->hStereoMdct, ivas_format, sts[ch_core]->element_mode, sts[ch_core]->element_brate, sts[ch_core]->bwidth, sts[ch_core]->igf, igf_grid, 0 );
+#else
+            initMdctStereoEncData( hMCT->hBlockData[ch]->hStereoMdct, ivas_format, sts[ch_core]->element_mode, sts[ch_core]->element_brate, sts[ch_core]->bwidth, sts[ch_core]->igf, sts[ch_core]->hIGFEnc->igfData.igfInfo.grid, 0 );
+#endif
         }
 
         if ( sts[ch_core]->igf )
diff --git a/lib_enc/ivas_mct_enc.c b/lib_enc/ivas_mct_enc.c
index ff248f7f33b58c368bdb57571b0d6bc4452be457..253ba48c166a63bb92f4b44d1c775db48291b6a4 100644
--- a/lib_enc/ivas_mct_enc.c
+++ b/lib_enc/ivas_mct_enc.c
@@ -172,7 +172,9 @@ ivas_error ivas_mct_enc(
     float orig_spectrum_long[MCT_MAX_BLOCKS][CPE_CHANNELS][L_FRAME48k];
     int16_t switch_bw;
     IVAS_FORMAT ivas_format;
+#ifndef NONBE_FIX_986_MC_BW_SWITCHING
     int16_t max_bwidth;
+#endif
     int32_t ivas_total_brate;
     ivas_error error;
     float *pdata[MAX_INPUT_CHANNELS];
@@ -186,7 +188,9 @@ ivas_error ivas_mct_enc(
     hMCT->hBstr = st_ivas->hCPE[0]->hCoreCoder[0]->hBstr; /* pointer to write MCT side bits */
 
     ivas_format = st_ivas->hEncoderConfig->ivas_format;
+#ifndef NONBE_FIX_986_MC_BW_SWITCHING
     max_bwidth = st_ivas->hEncoderConfig->max_bwidth;
+#endif
     ivas_total_brate = st_ivas->hEncoderConfig->ivas_total_brate;
 
 #ifdef DEBUG_FORCE_MCT_CP
@@ -230,7 +234,11 @@ ivas_error ivas_mct_enc(
 
         for ( n = 0; n < (int16_t) ( hMCT->nchan_out_woLFE * 0.5 ); n++ )
         {
+#ifdef NONBE_FIX_986_MC_BW_SWITCHING
+            initMdctStereoEncData( hMCT->hBlockData[n]->hStereoMdct, ivas_format, IVAS_CPE_MDCT, cp_bitrate, st_ivas->hCPE[0]->hCoreCoder[0]->bwidth, st_ivas->hCPE[0]->hCoreCoder[0]->igf, st_ivas->hCPE[0]->hCoreCoder[0]->igf ? st_ivas->hCPE[0]->hCoreCoder[0]->hIGFEnc->igfData.igfInfo.grid : NULL, 0 );
+#else
             initMdctStereoEncData( hMCT->hBlockData[n]->hStereoMdct, ivas_format, IVAS_CPE_MDCT, cp_bitrate, max_bwidth, st_ivas->hCPE[0]->hCoreCoder[0]->igf, st_ivas->hCPE[0]->hCoreCoder[0]->igf ? st_ivas->hCPE[0]->hCoreCoder[0]->hIGFEnc->igfData.igfInfo.grid : NULL, 0 );
+#endif
         }
     }