Instead of using a combined case statement with conditional argument to
peer_stale() just split the cases and call peer_stale() accordingly.

-- 
:wq Claudio

Index: rde.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/rde.c,v
diff -u -p -r1.614 rde.c
--- rde.c	15 Jan 2024 15:44:50 -0000	1.614
+++ rde.c	23 Jan 2024 10:00:10 -0000
@@ -449,9 +449,10 @@ rde_dispatch_imsg_session(struct imsgbuf
 
 			switch (imsg_get_type(&imsg)) {
 			case IMSG_SESSION_STALE:
+				peer_stale(peer, aid, 0);
+				break;
 			case IMSG_SESSION_NOGRACE:
-				peer_stale(peer, aid,
-				    imsg_get_type(&imsg) == IMSG_SESSION_NOGRACE);
+				peer_stale(peer, aid, 1);
 				break;
 			case IMSG_SESSION_FLUSH:
 				peer_flush(peer, aid, peer->staletime[aid]);