Left game bug

When I've joined some team builder games when ive minimized the screen it has told the team I left group and no longer shows me in the group. When i went back to the team I'm still the group and can talk to them but they cant see me in the group and it shows them having other players they've added. I then tried to select find anther group and I get an error saying group not found. This has happened a couple times when I have minimized my game while waiting in group.