I have not personally experienced this, but have witnessed it and seen others talk about it.
Recently a glitch has sprung up that so,metimes when you are sitting, you are unable to interact with cards without being booted. Simply loading a deck to yourself can get you booted and noone sitting is guilty of doing anything to you. You go and sit, try to draw, get booted. Play a card from hand? get booted.
This sounds like you are in a proxy game and exceed your transfer rate quota. This shouldn't happen unless you are doing something unusual. I can troubleshoot with you to see what data you're sending. It is probably a media file.