What happened was this:
-My opponent played a Shifting Scroll, which had turned into Explosive Runes
-I played Kabal Lackey, which activated the secret
-The damage was dealt to Kabal Lackey, and then to my hero
-However, the image of Shifting Scroll remained on screen (it did not change to show Explosive Runes) as did the 2/0 damaged Kabal Lackey
-I tried to play Frostbolt, and use my hero power
-Both animations began, and remained on the screen (the effects of the card and hero power did not occur)
-I pressed the end turn button, and my turn did not end; all effects remained on screen
-I could see my opponent moving cards in their hand, however I could not see them play anything
My friend, who was spectating the game, said the match continued normally on his end. The effects of my cards resolved, my turn ended, my opponent played cards, and their effects resolved. When it reached my next turn, the timer ran out, and it continued into my opponents turn, and they eventually won the game. Despite this, my game continued in the same frozen state, with animations playing.
I recorded a video of my screen in the frozen state:
https://imgur.com/a/Mzpt2tC