I don't know if this is a known bug but I was doing the 1hp challenges and realised that Lifesaving Block doesn't activate if you are standing on Mud Pit terrain. Happened twice in the same game. At first I thought I was facing the wrong way but at the second instance I am positively sure I was facing the opponent. Can someone else confirm this? It happened at Slimy Foyer, the 1st level of Dungeon Of The Swamp King.
Mud Pit isnt difficult terrain only but has an effect, the effect being that any block in your hand gets inactive while youre in the mud. It says: 'Target may not block while in Mud'.
