diff --git a/lib_com/options.h b/lib_com/options.h
index 58337d6abe88d64a1382387104a34812259c42d2..b26b2d81c5f0f695f95604719a7d6e4149afb06c 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -171,6 +171,7 @@
 /* all switches in this category should start with "NONBE_" */
 
 #define NONBE_FIX_1176_OSBA_REVERB_JBM_ASAN_ERROR       /* Ericsson: Issue 1176, fix in TDREND_firfilt for subframes shorter than the filter length */
+#define NONBE_1240_FIX_CORE_SELECTION_ISM_SW            /* VA: issue 1240: Remove the forcing of the TCX core in ISM when switching from a high bitarte to a low one */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_enc/ivas_decision_matrix_enc.c b/lib_enc/ivas_decision_matrix_enc.c
index 306aaf74b6581a0f503e399273a457fc05cb709e..2b0f688226d355786fc0a075400f56f6c3c39715 100644
--- a/lib_enc/ivas_decision_matrix_enc.c
+++ b/lib_enc/ivas_decision_matrix_enc.c
@@ -172,7 +172,12 @@ void ivas_decision_matrix_enc(
         st->core = ACELP_CORE;
     }
 
+#ifdef NONBE_1240_FIX_CORE_SELECTION_ISM_SW
+    /* sanity check: highest bitrates in ISM */
+    if ( st->is_ism_format && st->tcxonly && st->total_brate > MAX_ACELP_BRATE_ISM )
+#else
     if ( st->is_ism_format && st->tcxonly )
+#endif
     {
         st->core = TCX_20_CORE;
     }