The Lunge Strike (1st polearm attack skill) sometimes destroys 1 or 2 wall blocks in its area of effect. I couldn't catch the rule of it - sometime it works, sometime doesn't. Not all walls are affected by this - slim walls seem to be more suspectible. It seems that if there is a monster between the player and a wall, the chance to dig is higher. I couldn't reprodice bug with lvl 1 hero, but after that I got 2nd level (put skill point into clockwork knight) and hit a monster near the wall with lunge strike - it started to dig accidently. I have all three expansion installed.
