What's up with being added as a spectator?

[Snowcrash000]

This is something that happens to me every now and then, without any discernible reason. I queue up for a game, confirm that I want to enter and when the game starts, I'm a spectator and cannot actively play it. Is this a known bug or somehow working as intended even though it does not seem to make any sense at all? It's rather frustrating to queue up for a game for several minutes and then being unable to play because you somehow get added as a spectator for no reason that I can see.

[MrBeardy]

How is your net connection? Is this a lag/latency thing generally in all games or is it happening in one particular game? I've not seen it personally bar once or twice when I was on a very poor public wi-fi. But then it usually doesn't let me accept to join the game you just get the "game in progress all players have accepted" screen so you know not to bother before getting into the game itself.