diff --git a/lib_com/options.h b/lib_com/options.h
index a0981ebad3c31d1295cffd7df044e93c6b9e68ff..69bed8bf8764ef58bdcb78d1f80c71b4dfbe696a 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -244,6 +244,8 @@
 #define FIX_570_TCX_LPC_WRITE                           /* FhG: fix issue 570: LPC bitstream writer in TCX */
 #define FIX_506                                         /* FhG: Compiler warnings */
 #define FIX_511_OPTIMIZE_PARAMBIN_GAIN_FETCH            /* Nokia: Issue 511, significant optimization of parametric binauralizer gain fetching. */
+#define FIX_531_BWS_ISM_BFI                             /* VA: issue 531: fix MemorySanitizer: use-of-uninitialized-value in ISM2 rate switching with frame errors */
+
 
 /* ################## End DEVELOPMENT switches ######################### */
 /* clang-format on */
diff --git a/lib_dec/ivas_core_dec.c b/lib_dec/ivas_core_dec.c
index 9d6211bf8f56e6508b593c3a41feb509c85a6465..3367cd5d718b68730c4df3fbc3d464d623ee1bf6 100644
--- a/lib_dec/ivas_core_dec.c
+++ b/lib_dec/ivas_core_dec.c
@@ -504,7 +504,11 @@ ivas_error ivas_core_dec(
          * SWB(FB) BWE decoding
          *---------------------------------------------------------------------*/
 
+#ifdef FIX_531_BWS_ISM_BFI
+        if ( st->extl == SWB_TBE || st->extl == FB_TBE || ( st->coder_type != AUDIO && st->coder_type != INACTIVE && st->core_brate >= SID_2k40 && st->core == ACELP_CORE && !st->con_tcx && output_Fs >= 32000 && st->bwidth > NB && st->bws_cnt > 0 ) )
+#else
         if ( st->extl == SWB_TBE || st->extl == FB_TBE || ( st->coder_type != AUDIO && st->coder_type != INACTIVE && st->core_brate >= SID_2k40 && st->core == ACELP_CORE && output_Fs >= 32000 && st->bwidth > NB && st->bws_cnt > 0 ) )
+#endif
         {
             /* SWB TBE decoder */
             swb_tbe_dec( st, hStereoICBWE, bwe_exc_extended[n], voice_factors[n], old_syn_12k8_16k[n], tmp_buffer /*fb_exc*/, hb_synth[n], pitch_buf[n] );