[gf8552f7] Unknown cause, vehicle issue

When I saved the game my vehicle was facing east, after I finished fixing a few problems with the More Foods II PR I loaded up the game again and the vehicle was facing two turns to the south. Upon trying to correct this the player character began moving east when I started driving. Stopping the vehicle did not stop the PC’s movement and the vehicle seemed content to continue driving onward.

I have no idea what caused this but I can no longer continue this game. Here is the save file

The save indicates the player character is on a vehicle part at 4,-2 (the floodlight tot the south) where as he is actually one step to the north.
If you load the save and move onto that floodlight, a debug messages says that you’re already there. It than continues normally.
If you don’t move onto that floodlight, the vehicle part is still registered as boarded (has the passenger_flag).
During vehicle-movement that flag is checked and the player/npc with the matching id is moved along (regardless where the player/npc actually is).

That means the vehicle has the player character registered on part 4,-2, but the player character is on a different place. The vehicle does not care and moves him anyway.

This seems to be caused by the wrong direction of the vehicle. If it would face directly east, the whole area where the player is would be one step to the north and the character would be exactly on the floodlight, therefor on the assumed place and everything would be alright. So the question is why did the vehicle turn at all?