Today, I had Bloody Mary get stuck on a dock! I didn't think it would happen to a Captain but it sure did to me today.
I only lucked out of it because I happened to save the game right before her Frigate left the main map on a cruise to Panama.
She had to go through the cruise again but I had to stop playing while she was still out there so I can't tell you if she'll get stuck again until later. Here ARE some things that I noticed about the condition though - see if any of your observations were the same.
1) That the condition of a trapped pirate happens during a large game, usually when I have +400 total people on the island.
2) That incidents of characters just standing around seem to increase as the game gets larger and longer. I could not count the times when my builders would just stand beside the under construction building and complain that they were too scared to move and maybe if they just stood there no one would notice...Could too much scary decor be a factor for captives? If so, does too much defense cause the same response from pirates?
3) I did try the following before reloading the game for Bloody Mary: I demolished TWO of her destinations to no avail. Her third destination was her ship for rest as she had no house. (I have plenty of houses, but for some reason she never claimed any of the many plots I put out there from the time of her hire) Even though the dock she was stuck at had her ship moored to it, still no move.
4) I fired her and another pirate Captain and they swapped ships. That's as far as it went, though - she stayed stuck and Rock went around her without incident.
5) Being too busy - I was doing a lot of stuff at the time I discovered Mary stuck like the fly. I put through a press, a party and gave out a few cash awards along with ransoming my wealthy captives from her cruise. I am wondering if lag over these things being done as quick as I could move the mouse might have something to do with it - especially if she walked in to the wake of one of the captives that I ransomed fresh off the ship. Maybe the disappearing captive left a cyber hole that Mary tripped into. I dunno. Post up anything you found out folks. This seems to be a puzzler.