Got the same bug as Eitamnetal. After a few hits with the pillars (and from me) the snowman seems to lose track of where the pillars are and just keeps digging towards a corner. Almost endlessly, then he pops out again, firing a few rounds, before going in the same loop again.
Edit: I think I know what's happening. When the snowman starts digging, he selects a pillar to go to. If that pillar is up at the moment, he will go into that loop. He will get out of the loop when you lower the pillar he selected. Then hopefully he selects a pillar that is down and works as he should.