FS-3932 --resolve the change in switch_ivr_bridge was your issue

src/mod/applications/mod_dptools/mod_dptools.c

@@ -2902,6 +2902,12 @@ SWITCH_STANDARD_APP(audio_bridge_function)
 										v_campon_fallback_exten,
 										switch_channel_get_variable(caller_channel, "campon_fallback_dialplan"),
 										switch_channel_get_variable(caller_channel, "campon_fallback_context"));
+
+			if (peer_session) {
+				switch_channel_hangup(switch_core_session_get_channel(peer_session), SWITCH_CAUSE_ORIGINATOR_CANCEL);
+				switch_core_session_rwunlock(peer_session);
+			}
+
 			return;
 		}
 

src/switch_ivr_bridge.c

@@ -1244,6 +1244,7 @@ SWITCH_DECLARE(switch_status_t) switch_ivr_multi_threaded_bridge(switch_core_ses
 
 			if (!switch_channel_ready(caller_channel)) {
 				abort_call(caller_channel, peer_channel);
+				switch_core_session_rwunlock(peer_session);
 				goto done;
 			}