[Mondaveo]

I've had a few occasions where my front passenger door couldn't be opened from outside after unlocking the car, but each time it's been fixed by locking and then unlocking the car again. I suspect the mechanism is just sticking since it's only occurred intermittently (and I think I saw the lock toggle in a position not-quite unlocked). Alternative explanations are a short or break in the circuit or an actuator that's failing, but it hasn't been doing it recently.

In the case where it happens all the time, it does sound more like an actuator or electrical failure isolated to one door.