diff --git a/client/src/app/site/agenda/models/view-item.ts b/client/src/app/site/agenda/models/view-item.ts
index eb6c3f1d4..b0e244e68 100644
--- a/client/src/app/site/agenda/models/view-item.ts
+++ b/client/src/app/site/agenda/models/view-item.ts
@@ -125,6 +125,7 @@ export class ViewItem extends BaseViewModel {
 
     public updateDependencies(update: BaseViewModel): boolean {
         if (
+            update &&
             update.collectionString === this.item.content_object.collection &&
             update.id === this.item.content_object.id
         ) {
diff --git a/client/src/app/site/users/models/view-user.ts b/client/src/app/site/users/models/view-user.ts
index 8afef1b58..b22c53324 100644
--- a/client/src/app/site/users/models/view-user.ts
+++ b/client/src/app/site/users/models/view-user.ts
@@ -206,21 +206,13 @@ export class ViewUser extends BaseProjectableViewModel implements Searchable {
         return this.full_name;
     };
 
-    /**
-     * TODO: Implement
-     */
-    public replaceGroup(newGroup: ViewGroup): void {}
-
     public updateDependencies(update: BaseViewModel): void {
-        if (update instanceof ViewGroup) {
-            this.updateGroup(update);
-        }
-    }
-
-    public updateGroup(group: ViewGroup): void {
-        if (this.user && this.user.groups_id) {
-            if (this.user.containsGroupId(group.id)) {
-                this.replaceGroup(group);
+        if (update instanceof ViewGroup && this.user.groups_id.includes(update.id)) {
+            const groupIndex = this.groups.findIndex(group => group.id === update.id);
+            if (groupIndex < 0) {
+                this.groups.push(update);
+            } else {
+                this.groups[groupIndex] = update;
             }
         }
     }