I've found that if I press "resign" at the same time my opponent is playing a card, the game gets stuck. i.e., the resign message doesn't appear on my screen, and I don't get returned to the multiplayer lobby. It just stays in-game, with nothing happening, and I'm unable to play any cards or do anything. The global chat still works, but nothing else does. This has happened to me twice (I haven't yet tested it to see if it happens every time). I've asked what happens from the other player's point of view, and they say that I've just resigned with nothing else weird happening. So the resign command has gone through, but the return-to-lobby part doesn't work for me (i.e. for the player resigning). As I said, I'm pretty sure that this bug is trigged by resigning while the other player is playing a card; as in, when the card being played is displayed on the screen. [edit] This happened to me a third and forth time. Apparently the problem occurs whenever I resign while it is the opponents turn, regardless of what they are doing. They could pass, play a card, or whatever. If I resign while it is their turn then I don't get returned to the multiplayer lobby. The game is stuck.
Hmm, I've tried to repro this and it doesn't happen for me if I just resign during an opponent's turn in MP. If you see it again, can you note what else is going on and/or take screenshot?
Ok, next time I intend to resign, I'll try to trigger the bug. My original guess was that it happened when they were playing a card; but I've since had it happen while they are moving someone with winds of war, and even just passing. In one of the cases I remember that there was a card stuck in the middle of the screen after the bug had happened, as though it was frozen mid-animation. My best guess is that it happens if the opponent does something at the same time as I'm resigning; perhaps it could be anything at all. I'm not sure. Anyway, I'll post again if I find out anything new.
Okay, pretty sure we have this figured out now. Not sure which build the fix will go up in though due to... well... a thing. A thing that will happen very soon.