So, I'm in The Triple Circle Mine. I ran past some mobs to leave without fighting them (there's only one type of mob in this mine), and one rammed into me as I reached the door. Upon getting body slammed by Captain Ugly... I went
THROUGH the door and out the other side. It was only a very slight knock back, but enough to apparently phase me through the wood.
I hope this is the right place, and way, to report this kind of bug. I don't see it being a huge issue, though it could potentially really mess someone up if it had shot me off the edge of the map rather than onto a stone landing behind the doorway, for example.