diff --git a/src/mod/endpoints/mod_sofia/mod_sofia.c b/src/mod/endpoints/mod_sofia/mod_sofia.c
index a9a459c054..3408e8aba6 100644
--- a/src/mod/endpoints/mod_sofia/mod_sofia.c
+++ b/src/mod/endpoints/mod_sofia/mod_sofia.c
@@ -722,8 +722,6 @@ static switch_status_t sofia_read_frame(switch_core_session_t *session, switch_f
 								tech_pvt->mismatch_count++;
 							}
 							
-							tech_pvt->last_codec_ms = codec_ms;
-							
 							if (tech_pvt->mismatch_count > MAX_MISMATCH_FRAMES) {
 								if (switch_rtp_ready(tech_pvt->rtp_session) && codec_ms != tech_pvt->codec_ms) {
 									const char *val;
diff --git a/src/switch_core_io.c b/src/switch_core_io.c
index 1d1730c0ae..990df63ef1 100644
--- a/src/switch_core_io.c
+++ b/src/switch_core_io.c
@@ -610,7 +610,7 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_write_frame(switch_core_sess
 	if ((session->write_codec && frame->codec && session->write_codec->implementation != frame->codec->implementation)) {
 		if (session->write_codec->implementation->codec_id == frame->codec->implementation->codec_id) {
 			ptime_mismatch = TRUE;
-			if (!need_codec) {
+			if (switch_test_flag(frame->codec, SWITCH_CODEC_FLAG_PASSTHROUGH) || switch_test_flag(session->read_codec, SWITCH_CODEC_FLAG_PASSTHROUGH)) {
 				status = perform_write(session, frame, flags, stream_id);
 				goto error;
 			}