diff --git a/roomserver/internal/perform_join.go b/roomserver/internal/perform_join.go
index 778c1b6b8..b92a6663b 100644
--- a/roomserver/internal/perform_join.go
+++ b/roomserver/internal/perform_join.go
@@ -204,7 +204,7 @@ func (r *RoomserverInternalAPI) performJoinRoomByID(
 		// a member of the room.
 		alreadyJoined := false
 		for _, se := range buildRes.StateEvents {
-			if !se.StateKeyEquals(*event.StateKey()) {
+			if !se.StateKeyEquals(userID) {
 				continue
 			}
 			if membership, merr := se.Membership(); merr == nil {