Yep, the PO had replaced the head gasket. Naturally I don't trust others work, so I took a look to make sure everything was good, which is how I found the twisted bolt. PO had put only 1 of the 2 required crush washers on also, which is probably why he tightened the crap out of it.
Went over the rear cylinder already, everything looks good. We'll see when the new parts arrive.