Clicked start after getting into an "undefined" room

[22:48:27] [Steam P2P] Closed session with 76561198326580445.
[22:48:27] [Steam P2P] Closed session with 76561198328591957.
[22:48:27] [Steam P2P] Closed session with 76561198010917616.
[22:48:27] [Steam P2P] Closed session with 76561198210572775.
[22:48:27] [Steam P2P] Closed session with 76561198219885903.
[22:48:27] [Steam P2P] Closed session with 76561198037901791.
[22:48:27] [Steam P2P] Closed session with 76561198150489689.
[22:49:03] LUA RUNTIME ERROR; Debugger halted if attached.
[22:49:03] [string "{9B0080A3-1539-5547-A5FD-E259DC937C08}"]:443: assertion failed!