Outcast

I'm playing through a map on champion difficulty. Following the advice above, I decided to take archers at the beginning. I discovered a bug with the Well of Luck - after defeating undead, I gained a level, agreed to lose some experience to cleanse the well, and lost a level. After that, I continued playing - experience increased, but I didn't gain new levels. Luckily, I had saves - I replayed it so that after defeating the undead near the well, I wouldn't level up, and everything was fine afterward.