Hi and welcome to our forum. Are you saying you had a recording set and then watched the recording 15 minutes after the recording stopped. If so this is known as chasing playback and should not affect the actual recording. If you skip the ads and go forward beyond the existing recording contents then playback will drop out to real time but it should not stop the recording completing. I do this with all ITV recordings. You can avoid dropping out of playback by using the forward skip key (which by default is set to + 2 mins), the key will stop working if less than 2 mins of recording is left. The forward and reverse skip keys are the best ways to skip ads as most are around 4 mins so two presses gets very close to the end of the ads, if you overshoot the reverse skip key backs up in 5 second skips unless you change the default settings.

Have you checked the actual recording length ? If you post which programme someone else may have recorded it and confirm the recording length they got. The broadcaster may have screwed up accurate recording signals.