We are having the same problem but it is not all programs we are trying to record. We are also getting some partial records and others where the picture is distorted.
I have good broadband at 60.5 m/bps from the BT location and the box is less than 2 metres from the hub with no walls to interfere.
We have tried to reset and like the other person would rather not to have factory reset. Had box we think 7+ years and apart from not recording the full programme on occasions, this has been the only incident.