So I came across something really odd today while I was doing Game of Death on auto.
I wasn't really looking, so I can't say what exactly triggered it, but what happened is that the Warrior CotD's extra turn was repeatedly triggering. The Warrior CotD had that buff on him where he can't go below 1HP (received from the Gunner CotD), and so my Grim Reaper was subjected to a death of a thousand cuts.
I was using Grim Reaper, Magus Allied Soldier and the Angel of Fear. By the time I checked my bat and soldier had both died, as well as the Gunner and Assassin CotD, but I still had a Reflect Shield up. Which took down the Magus CotD while the Warrior was needling my Reaper. A very odd occurrence, I've never seen anything like this and I reckon it only happens in very select circumstances. Of course, I can't say for sure whether this bug started happening due to the 12 Dec update.