I was fighting the final boss in Xibalba and my game froze when Youala Night Drinker was casting a spell. After restarting my pc, I got back there and my game froze again when the same minion was casting a spell. I think the specific spell he was using was Lord of Winter, but I'm not sure. This seems like a recurring bug recently, I hope it gets fixed soon.
Adding on to what I wrote earlier, I also noticed that blue razors can cast lord of winter so it is possible that that spell is bugged in some fights. Maybe the Morganthe ice minion tried casting lord of winter as well and it’s all the same issue.