--- main/rtp_engine.c	(Asterisk 13.6.0)
+++ main/rtp_engine.c	(working copy)
@@ -730 +750 @@
-			new_type->format = ao2_bump(ast_format_g726_aal2);
+			new_type->format = ast_format_g726_aal2;
@@ -732 +752,4 @@
-			new_type->format = ao2_bump(t->payload_type.format);
+			new_type->format = t->payload_type.format;
+		}
+		if (new_type->format) {
+			new_type->format = ast_format_parse_sdp_fmtp(new_type->format, "");