To the left of the screenshot, you can see some guests staying underwater. They have never moved since I noticed them, but the command k and v indicate that they are still alive.
I thought they were not able to climb up, so I channeled some ramps around the bank to help them, but they still remained there, without moving even a bit.
What's wrong with them?
Best Answer
Late reply, but this does appear to be a known bug: http://www.bay12games.com/dwarves/mantisbt/view.php?id=9254
The person confirming the bug report was able to get the visitor to path out of the water by clearing the visitor tag from the visitor using dfhack. I assume if you did that, you'd want to then reapply the visitor tag once they've pathed to the tavern.