diff --git a/gbproxy/GBProxy_Tests.ttcn b/gbproxy/GBProxy_Tests.ttcn
index 00f6e2e..62daaf4 100644
--- a/gbproxy/GBProxy_Tests.ttcn
+++ b/gbproxy/GBProxy_Tests.ttcn
@@ -526,6 +526,11 @@
 function f_cleanup() runs on test_CT {
 	var integer i;
 
+	/* To avoid a dynamic test case error we need to prevent messages arriving on unconnected
+	 * ports. Waiting here ensures that any messages "in flight" will be delivered to the port
+	 * before the component is shutdown and disconnected. */
+	f_sleep(0.2);
+
 	for (i := 0; i < lengthof(mp_nsconfig_sgsn); i := i+1) {
 		f_destroy_gb(g_sgsn[i]);
 	}