1. Version 54
2. MacOs 10.11.6
3. This is a fun one. Use of Ayneris's Rapier made a copy of an enemy overlaid on top of itself (ie. Marauder 5 underneath Marauder 5). After that the game acted like there was simply one more enemy to fight.
4. Not sure! Though I found it by repeatedly hitting F to get through battle quickly. So maybe it was interrupted?
6. This may be related to a bug where enemies sometimes attack out of turn on the first move. Sometimes simultaneously! In fact, I found that if I hit autoattack before the attack animation is done, I can go through the whole battle 5x quicker because all the attack animations are happening at the same time.