diff --git a/sys/net/pf/pf_ioctl.c b/sys/net/pf/pf_ioctl.c
--- a/sys/net/pf/pf_ioctl.c
+++ b/sys/net/pf/pf_ioctl.c
@@ -2086,6 +2086,7 @@
 			break;
 		}
 		bcopy(altq, &pa->altq, sizeof(struct pf_altq));
+		pa->altq.altq_disc = NULL;
 		break;
 	}