# UNDF: UNDF-2026-000000916
--- a/models/cards.js
+++ b/models/cards.js
@@ -2155,13 +2155,13 @@
+      const allowedSet = new Set(allowedMemberIds);
       const currentMembers = Array.isArray(this.members) ? this.members : [];
-      const filteredMembers = currentMembers.filter(memberId => allowedMemberIds.includes(memberId));
-      if (currentMembers.filter(x => !filteredMembers.includes(x)).length > 0) {
+      const filteredMembers = currentMembers.filter(memberId => allowedSet.has(memberId));
+      if (filteredMembers.length !== currentMembers.length) {
         mutatedFields.members = filteredMembers;
       }

       const currentWatchers = Array.isArray(this.watchers) ? this.watchers : [];
-      const filteredWatchers = currentWatchers.filter(watcherId => allowedMemberIds.includes(watcherId));
-      if (currentWatchers.filter(x => !filteredWatchers.includes(x)).length > 0) {
+      const filteredWatchers = currentWatchers.filter(watcherId => allowedSet.has(watcherId));
+      if (filteredWatchers.length !== currentWatchers.length) {
         mutatedFields.watchers = filteredWatchers;
       }