Hello!
I have a problem with a passenger door in my '03 r53.
When I'm unlocking the car remotely, only driver side door unlocks, and the other one stays locked. When I pull the passenger door handle from inside, the door unlocks. Once it's unlocked, I'm able to remotely close it again. The inside door handle feels a bit weird. Also, the weather was a bit harsh in the last week. The temperature went down to -20°C (-4°F). Everything was working fine before.
What could be the reason of this?

Edit.
After a few days, everything got back to normal. No problems with the door so far.

 

Mine 03 S is programmed to unlock the driver's door on the first click and then unlock the passenger door and rear hatch on the second click

 

I had the same problem with mine (trying to remember if it was driver or passenger side). It turned out to be the door lock unit ~$100 as I recall. I took the door apart and was able to determine by watching what was going on that it was in the unit itself (unfortunately I don't remember how) but if I figured it out you probably can too.