Attack/end turn button gone. Forced to concede. Happened three times tonight.

https://i.imgur.com/E6534cV.jpg

Yeah, so three times tonight, while trying to test a deck in gauntlet, this happened. I was forced to concede. I tried quitting and re-opening the game to no effect. Gave up trying to play after the third time, feeling very frustrated.

Edit: I submitted a bug report when it happened. Curious if anyone else has noticed anything similar?

Edit II: Just happened again, this time in draft. http://i.filmot.org/ENsL8Gk.png Aaand, just noticed it was again right after playing stash, and someone else posted same below!! I think it happens after stashes, either all the time, or when one or more of the weapon slots is not used.