When playing a challenge round the status often remains as available. This announce incorrectly that the person playing a challenge is available.
Either default to busy whenever in a game or allow a pause by save so that Multiplayer round can be accepted in real time.
This would allow the completion of the challenge without missing the real time event with community members who are online.
Hate to loose a good game but hate to miss the chance to play a friend when it is available.