Merge pull request #8268 from obrakmann/fix8262_d2k_double_remove_from_world

Fix potentially removing actors twice from world in Actor::ChangeOwner

OpenRA.Game/Actor.cs

@@ -242,11 +242,16 @@ namespace OpenRA
 					return;
 
 				var oldOwner = Owner;
+				var wasInWorld = IsInWorld;
 
 				// momentarily remove from world so the ownership queries don't get confused
+				if (wasInWorld)
 					w.Remove(this);
+
 				Owner = newOwner;
 				Generation++;
+
+				if (wasInWorld)
 					w.Add(this);
 
 				foreach (var t in this.TraitsImplementing<INotifyOwnerChanged>())