Rear lock problem with central locking

[Stockysan]

Anyone know the likely problem when one of the rear doors won't unlock via central locking? I can still unlock it manually from the inside, but not from the key fob or driver's controls. Keen to know if it is a common fault, and what the problem likely is. The lock still moves when I try to unlock it using central locking, but it springs back to the locked position.
Any help appreciated
Andrew

 

[luke_84]

I'd say the door lock actuator itself is faulty.