diff --git a/lib_com/options.h b/lib_com/options.h
index 1e56a65dcfe2ed30c9cd3ed7bfc15f2ddeefcca6..8e314ba4f1678e9adc9176adfe608dcc7f64492c 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -175,6 +175,7 @@
 #define REVERT_ZERO_FLUSH_TRESH                               /* FhG: issue 1069: revert threshold value introduced with !1518 due to significant complexity increase*/ 
 #define NONBE_FIX_1097_SBA_DTX_BRATE_SWITCHING_ENC            /* FhG: fix out-of-bound errors when switching from SID frame to active frame*/
 #define NONBE_FIX_1110_STEREO_DTX_BRATE_SWITCHING             /* VA: issue 1110: fix encoder crash in the stereo DTX bitrate switching condition */
+#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 */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_dec/acelp_core_dec.c b/lib_dec/acelp_core_dec.c
index a1ea41894b870034c602dc14d8ecb738c6d6e0cf..d444c03ea786cb92055282814f6e424f506f5a33 100644
--- a/lib_dec/acelp_core_dec.c
+++ b/lib_dec/acelp_core_dec.c
@@ -703,7 +703,11 @@ ivas_error acelp_core_dec(
                 old_exc_s = st->old_exc + L_EXC_MEM_DEC - st->L_frame;
                 tmpF = *old_exc_s;
                 st->mem_deemph = old_exc_s[st->L_frame - 1];
+#ifdef NONBE_1131_ACELP_OOB
+                preemph( old_exc_s, st->preemph_fac, st->L_frame, &tmpF );
+#else
                 preemph( old_exc_s, st->preemph_fac, L_FRAME16k, &tmpF );
+#endif
                 mvr2r( old_exc_s + st->L_frame - M, st->mem_syn2, M );
                 residu( Aq, M, old_exc_s, old_exc + L_EXC_MEM_DEC - st->L_frame, st->L_frame );
             }