I was playing survival in Charon and started in spectator mode of course. I hit tab to bring up the leader board. Eventually it was my turn to spawn and the in-your-face mission briefing rectangle texture popped up. The only way that I know to dismiss that is to move, but my controls were locked. It took me several seconds to realize that the leader board was still open behind that and locking out my controls until I hit tab to dismiss the leaderboard.
When you spawn the leaderboard should probably close. At the very least it should close if the mission briefing pops up.
While on the topic, that mission briefing itself is also kinda annoying because I can't see where I'm going before I dismiss it and I can't dismiss it without going. Maybe shooting should dismiss it too?