I got totally screwed by this, I was on a tier 3 ice arena, not only I have trouble there because despite having an grey owlite shield a freeze lumber hit does a whole lot of damage and freezes me regardless of shield, on another run I had my shield just decided to stay broken, which meant real trouble (I only carry a sword, not rich enough to buy another weapon yet like a bomb or at least a good gun, my frost gun does pitiful damage). I could still shield bump, but I had to stay out of attack range at all times because the shield didn't absorb damage. Needless to say I died on a lag spike.
While I am at it, maybe it is just the lumber problem I said but I assumed the ice would break if I got hit with the shield up, but didn't. which meant getting hit by them was death after I used all my restoration pills (because like I said even if I shield the hit I still get frozen).
Did the Lumber break through your shield when it froze you? Or were you standing in a dead Ice Cube's freeze cloud? Those gas clouds, including the ones from Greavers, bypass shields.