It's really good to type out what the bug is even if you have a video, especially since the videos seems to be also telling what the bug is but it's taking awhile to get to the point.
However that's not a bug and has existed in all version of the game. NPCs put prisoners in nearest neutral prison and if that happens to be yours you get the ransom when they eventually get ransomed and are also free to take them out and ransom them at a tavern yourself with no relation penalty or any such things.