When I knew I had lost the match, I decided to end it on my own terms by using "Krav, Unredeemed" to take 6 health away from myself. I expected the defeated animation to play and to exit the match automatically. Instead, idropped to -4 HP, I was unable to interact with most of the UI including the settings menu. I was able to open up the recent plays "scroll", in case it's more complicated than I originally thought.
The idle card animations and character portraits continued as normal, and I could tap on those, but no voicelines worked. I closed the game and reopened it. No progress was lost for my goals and everything else seems to be fine.