Fixing issue if group was deleted when out of bounds.

back/src/Model/GameRoom.ts

@@ -312,7 +312,6 @@ export class GameRoom {
         }
         group.leave(user);
         if (group.isEmpty()) {
-            this.positionNotifier.leave(group);
             group.destroy();
             if (!this.groups.has(group)) {
                 throw new Error(`Could not find group ${group.getId()} referenced by user ${user.id} in World.`);

back/src/Model/Group.ts

@@ -141,6 +141,10 @@ export class Group implements Movable {
      * Usually used when there is only one user left.
      */
     destroy(): void {
+        if (!this.outOfBounds) {
+            this.positionNotifier.leave(this);
+        }
+
         for (const user of this.users) {
             this.leave(user);
         }