See edited description :)

This happened twice during gameplay for me (W8.1 64bit) - There doesn't seem to be any solid way to replicate it, although at first I thought it might be linked to being both very hungry and very thirsty - don't know whether there is a connection there.

I have tried this out, but haven't found this issue... It could depend on the dock, I guess.

This occured twice for me, both times after conflict. I do think it has something to do with becoming unconscious after combat. I fell out of a building and it didn't occur; I got hit in the head with a baseball bat and it did.