I searched and couldn't find any mention of this (so if it's been posted before, Mods, please feel free to merge or move or something LoL).
So, I had been staffing vets for a quest in Fort Charles, and randomly fell through the floor of the fort. It had happened before, but my pirate had always popped back up when I tried to move. This time...not so much:
(swimming backwards)
I could swim through walls and up and down some of the stairs, couldn't interact with anything (including the door to PR), and no enemies would attack me. I finally got out of it by swimming out of the fort into the ocean and then swimming back in.