diff --git a/lib_com/options.h b/lib_com/options.h
index e0f1ebbe9739edb36194393496a3df818eabb4db..e6367bd941bce8caa6f3aa0df86c5af2c6cf75f1 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -128,6 +128,7 @@
 #define NONBE_SVD_OPTIMIZATION 
 #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_1131_ACELP_OOB                            /* VA: issue 1131: fix division-by-zero in acelp gain decoding caused by wrong length of buffer update when switching from HQ core to ACELP core */
+#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 */
 #define FIX_1101_CLEANING_JBM_CALL                      /* VA: issue 1101: remove obsolete call of ivas_jbm_dec_tc_buffer_open() */
 
 
diff --git a/lib_enc/ivas_decision_matrix_enc_fx.c b/lib_enc/ivas_decision_matrix_enc_fx.c
index bd63553bd70f502ee2ad342de594d6ade28caf07..d01af3b23e40d4e98e23df6ee9b2f86663fc0d00 100644
--- a/lib_enc/ivas_decision_matrix_enc_fx.c
+++ b/lib_enc/ivas_decision_matrix_enc_fx.c
@@ -197,14 +197,6 @@ void ivas_decision_matrix_enc_fx(
             move16();
         }
     }
-
-    test();
-    test();
-    test();
-    test();
-    test();
-    test();
-
 #ifdef DEBUG_FORCE_DIR
     if ( st->force_dir[0] != '\0' )
     {
@@ -217,14 +209,26 @@ void ivas_decision_matrix_enc_fx(
 #endif
 
     /* do not allow TD stereo ACELP core -> DFT stereo TCX core switching as it is on the WC complexity path */
+    test();
+    test();
+    test();
+    test();
+    test();
+    test();
     if ( ( ( st->last_core == ACELP_CORE && EQ_16( last_element_mode, IVAS_CPE_TD ) && EQ_16( st->element_mode, IVAS_CPE_DFT ) ) || ( EQ_16( st->tdm_LRTD_flag, 1 ) && LE_32( st->total_brate, IVAS_16k4 ) ) ) && EQ_16( st->core, TCX_20_CORE ) && LE_32( st->total_brate, MAX_ACELP_BRATE ) ) /* Override TCX in case of LRTD && primary channel has low bitrate*/
     {
         st->core = ACELP_CORE;
         move16();
     }
 
+    /* sanity check: highest bitrates in ISM */
+    test();
+#ifdef NONBE_1240_FIX_CORE_SELECTION_ISM_SW
     test();
+    if ( st->is_ism_format && st->tcxonly && GT_32( st->total_brate, MAX_ACELP_BRATE_ISM ) )
+#else
     if ( st->is_ism_format && st->tcxonly )
+#endif
     {
         st->core = TCX_20_CORE;
         move16();