(I'm not sure if this is the pic, but it was something like a death screen that wouldn't load)
So, a couple days ago I decided to play some saga to try out a funny little deck until I remembered proving grounds doesn't exist anymore
So I went to campaign and ended up with this screen. Iirc, it was pitch black and it wouldn't load at all. It was fixed after re-opening the game, but I still have no idea why this occured.
This happened in offline mode I think, not the worst bug I've encountered but still a bit annoying