I was playing the Great Khan scenario with a couple of friends, and all three of us ended up in a manual battle. In this battle I only had one unit of Lost Souls.
These Lost Souls died, but then never revived (undying). I realised that this must be because they were my only unit, so I wasn’t actually getting any more turns (and thus the counter wasn’t being decremented). Usually that makes perfect sense, but in an allied battle, surely they should revive if you’re allies are still fighting? I guess it’s not really a “bug” per-say, but I did feel like it was an issue that warranted some discussion/attention.