LobbyManager: can't start new game after RETURNING to Lobby

I'm running into show-stopping, yet very strange and intermittent (2 out of 3 times roughly) network bug. I'm seeing this pattern:

1. Enter Lobby scene, Instantiate Unity Lobby prefab (from Asset Store) to allow players to choose create or join a game. For this, we always create games
2. choose 'create game' (one of 4 network scenes), start game, others join until complete and count-down runs to zero
3. Enter game scene, game commences, eventually game is done
4. Exit game scene
5. Return to the lobby scene with original lobby manager still working (don't destroy on load active on lobby manager)
6. Kill original lobby manager, shut down server, create a new lobby manager
7. When I now try to create a new game, 2 out of 3 times I get the dreaded 'A connection has already been set as ready. There an be only one' error.

Other that I'm really starting to hate 'Highlander', can anyone tell me where this comes from and how I can work around it? This is the last thing holding us up, and after two weeks of trying to get to the bottom of this, I'm starting to get desperate. Why isn't it happening every time? What is causing it? When is it caused? Why doesn't it trigger OnServerError? Why? WHY????

Anyone?

Thanks for any pointers.

-ch

 

Bumping this thread, because I'm experiencing the same problem, and can't for the life of me figure out why.