diff --git a/sys/net/pf/if_pfsync.c b/sys/net/pf/if_pfsync.c
--- a/sys/net/pf/if_pfsync.c
+++ b/sys/net/pf/if_pfsync.c
@@ -971,7 +971,8 @@
 				    "update start\n");
 			break;
 		case PFSYNC_BUS_END:
-			if (mycpu->gd_time_seconds - ntohl(bus->endtime) >=
+			if (sc->sc_ureq_sent != 0 &&
+			    mycpu->gd_time_seconds - ntohl(bus->endtime) >=
 			    sc->sc_ureq_sent) {
 				/* that's it, we're happy */
 				sc->sc_ureq_sent = 0;