I've found a castle dungeon on my way to one of the compact machines, at least I found what was left of one. I got a dozen or so unlit torches, an angel block, and almost 6 stacks of doors.I have not seen any on my limited travels, I have not even found a deep dark castle dungeon.
EDIT: Also, I seem to have found another bug. My Magma crucible didn't have any of the default augments when I crafted it. I spawned in and crafted a few more and it didn't happen again, but I ran into a similar issue with the Nullifier which is always missing the Integrated Servo Mechanism augment.