I got disconnected from the servers while playing a traditional draft round, and after I lost, the menus for sideboarding were completely broken, leading to a cosmetic menu with nothing showing up. I used escape to get to the arena menu and see if this one worked, it seemed so, and the sideboarding menu changed again, in another broken and unusable way. After doing the operation an additional time, I ended up on the classic sideboarding menu, except my deck didn't show up, only my leftover cards from the draft. I could click on the arrow hiding and showing the main deck again, which made the main deck appear, and could start sideboarding, but after that couldn't join the game (the buttons Back and Done did nothing) and had to concede the round to leave the menu, I couldn't do anything else and join my match.