We definitely had a cold soak issue on one of our A330s. There was a very short taxi in from the runway at our destination and after an ~ 8 hour flight, the APU would not start.
If we turned the master switch on at around 8,000' during approach, the APU would start normally on first attempt when we taxiied in.
My thoughts are that something in the APU or the APU bay was freezing up, preventing it working and this might have been due to a missing APU door seal or similar, which allowed cold air to circulate the APU bay during the cruise.
By opening the APU inlet during approach, the warm Caribbean air was able to defrost whatever it was that was affected, and the APU fired right up just after we landed.
Never got to the bottom of it, but the 'fix' worked !