This sounds like the original bug that the HDR-FOX-T2 had. If using padding the box wakes at the set time without the pre 15 minute boot to watch for the broadcaster accurate recording start signal. As a result the epg never gets updated, thus losing a days epg at the end of every day. It's very easy to see this in action. Turn on padding and every day on first boot remove the aerial and check the epg for 7 days time is not there. If you do this for several days you can see the epg shrink.
There's a very simple workaround. Set a daily manual watch reservation on say BBC1 for 20 mins to update the epg (OR a daily power on/off 20 minutes apart).