Host crashing from late joins after a level has been streamed, unloaded then restreamed


So i have a weird issue, if i host a game and people join before we start (so i have the first game map loaded in addition to lobby map) we can play lots of games without any crashes (this involves unloading and loading that game map through level streaming)

However, once I’ve done 1 full cycle (load the level, unload the level then load the level) the host will crash after someone has joined. I’ve validity guarded every possible reference of objects i can find so I’m not sure whats happening but i’m getting an —"LogWindows:Error: Assertion failed: ObjectOuter != NULL [File:D:\Build++UE4+Release-4.14+Compile\Sync\Engine\Source\Runtime\Engine\Private\PackageMapClient.cpp] [Line: 576] "—

Here is a link to my crash log, normally i don’t post questions but i’m really scratching my head on this one.

Thanks for any help!

So the issue stemmed from me having an actor that simulated physics in the map. After switching it to be dynamically spawned through my game state rather than it being placed in the level manually the crashes stopped.

For future Googlers, check out this udn post for more details and a potential fix if you have a multiplayer game with streaming: