R34 Sedan doors locking themselves

[OSH1FT]

I'm purchasing a 34 sedan that i'll be picking up later this week.

When I Inspected the car, the owner explained that the central locking has shat itself, while it keeps the car locked all the time, you need to hold the door lock open to open a door, and it immediately locks itself again.

While this sounds like a terrible aftermarket central locking problem (car has an immobilizer, so assume some sort of aftermarket central locking) I wanted to see if anyone else had the same problem with factory door locks and kinda hoping theres a simple fix.

Cheers!