Yesterday I was in a M+ run, AraKara 13. Suddenly I was disconnected. After logging back in, I learned that the whole group was disconnected all at the same time. We then found ourselves in a bubble at the beginning of the dungeon. Unable to leave the dungeon, unable to go further in the dungeon. Out of options, we voted to abandon the key. The vote passed and it ported us back to the exact same spot. Still unable to leave or progess. So we hearthed out, but then we all got messages that we would be flagged as deserters. Someone (not me) left the group, then another, then another. Group was disbanded. I got the “you need to return to the dungeon or be flagged as a deserter” message. I returned to the dungeon, the message reset itself. I joined a new group, the message restarted again. That group disbanded without ever starting a key. The message reset again and timed out.
Now I have a deserter buff “for repeatedly deserting”, but I never deserted anything once, let alone many times.