diff --git a/daemon/call.c b/daemon/call.c
index d133c25b2..83eb86ed0 100644
--- a/daemon/call.c
+++ b/daemon/call.c
@@ -2701,13 +2701,13 @@ static void __media_init_from_flags(struct call_media *other_media, struct call_
 		}
 	}
 
-	/* moved as plain text attributes, required later by sdp_create()
-	 * extmap
-	 * other (unknown type)
-	 */
-	if (media) {
-		t_queue_clear_full(&media->sdp_attributes, sdp_attr_free);
-		media->sdp_attributes = *additional_attributes;
+	if (flags->opmode == OP_OFFER || flags->opmode == OP_ANSWER || flags->opmode == OP_PUBLISH) {
+		/* moved as plain text attributes, required later by sdp_create()
+		 * extmap
+		 * other (unknown type)
+		 */
+		t_queue_clear_full(&other_media->sdp_attributes, sdp_attr_free);
+		other_media->sdp_attributes = *additional_attributes;
 		t_queue_init(additional_attributes);
 	}
 
diff --git a/daemon/sdp.c b/daemon/sdp.c
index 8f3abfdb3..db4a9a83f 100644
--- a/daemon/sdp.c
+++ b/daemon/sdp.c
@@ -2149,7 +2149,16 @@ static void insert_codec_parameters(GString *s, struct call_media *cm,
 }
 
 void sdp_insert_media_attributes(GString *gs, union sdp_attr_print_arg a, const sdp_ng_flags *flags) {
-	for (__auto_type l = a.cm->sdp_attributes.head; l; l = l->next) {
+	// Look up the source media. We copy the source's attributes if there is only one source
+	// media. Otherwise we skip this step.
+
+	if (a.cm->media_subscriptions.length != 1)
+		return;
+
+	__auto_type sub = a.cm->media_subscriptions.head->data;
+	__auto_type sub_m = sub->media;
+
+	for (__auto_type l = sub_m->sdp_attributes.head; l; l = l->next) {
 		__auto_type s = l->data;
 		if (s->type == SDP_ATTR_TYPE_EXTMAP && flags->strip_extmap && !MEDIA_ISSET(a.cm, PASSTHRU))
 			continue;
diff --git a/t/auto-daemon-tests-pubsub.pl b/t/auto-daemon-tests-pubsub.pl
index 921021377..77ce37183 100755
--- a/t/auto-daemon-tests-pubsub.pl
+++ b/t/auto-daemon-tests-pubsub.pl
@@ -117,6 +117,9 @@ m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=label:1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
@@ -153,6 +156,9 @@ m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=label:1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
@@ -189,6 +195,9 @@ m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=label:1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
@@ -226,6 +235,9 @@ m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=label:1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=inactive
 a=rtcp:PORT
 SDP
@@ -262,6 +274,9 @@ m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=label:1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
@@ -1158,12 +1173,18 @@ m=audio PORT RTP/AVP 0 8
 c=IN IP4 203.0.113.1
 a=rtpmap:0 PCMU/8000
 a=rtpmap:8 PCMA/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 m=audio PORT RTP/AVP 0 8
 c=IN IP4 203.0.113.1
 a=rtpmap:0 PCMU/8000
 a=rtpmap:8 PCMA/8000
+a=b-dummy
+a=b-foo:bar
+a=b-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
@@ -3299,6 +3320,9 @@ a=s-baz:quux blah
 m=audio PORT RTP/AVP 0
 c=IN IP4 203.0.113.1
 a=rtpmap:0 PCMU/8000
+a=m-dummy
+a=m-foo:bar
+a=m-baz:quux blah
 a=sendonly
 a=rtcp:PORT
 SDP
diff --git a/t/auto-daemon-tests.pl b/t/auto-daemon-tests.pl
index 674e83bea..558322e5a 100755
--- a/t/auto-daemon-tests.pl
+++ b/t/auto-daemon-tests.pl
@@ -1574,6 +1574,7 @@ a=rtpmap:118 AMR/8000
 a=fmtp:118 mode-set=0,2,4,7;mode-change-period=2;mode-change-capability=2;mode-change-neighbor=1;max-red=0
 a=rtpmap:98 telephone-event/8000
 a=fmtp:98 0-15
+a=msi:mavodi-0-15b-6c6-2-ffffffff-d3c00000-6005c95738e64-171f-ffffffffffffffff-@127.0.0.1-127.0.0.1;UAG-ELL-45-108
 a=sendonly
 a=rtcp:PORT
 a=ptime:20