Lewk: I have also noticed these issues plus a new one we came across in the last few days is that with series recording we have got two recordings showing for one episode. Both went for around 36 minutes and stopped and then you have to go to the second recording to continue. This happened with two episodes of Manifest and I am sure that we didn't have any other programs scheduled to record at the same time..
If the two recordings are on the same channel and the second immediately followed ....
Try reducing your PVR settings start offset to1minute and the end offset to 3 minutes or less. That way the first recording should finish before the PVR decides it has to force it to finish in order to start the second recording.