Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
I would start with drivers window down, and the car unlocked, monitor the RHF door lock snib button. The RHF door Is the master.
Could be the RHF door lock, could be in the switch assembly in the RHF door trim, or a wiring fault within the RHF door.
How often it occurs will be the determining factor as to how you will find it.
You should be able to find some parts at a wrecker to try first.