It would be common for people to record say several weekly episodes of a series, when they are away for a few weeks. If this failed, it would be crap, but more to the point it would get noticed. I am thinking about this as a software person. You can do a lot of crap stuff which for various reasons will never be discovered, but this one would be.
I did a google on this purposed Humax issue and yes it does confirm it, but it also says the box updates the EPG overnight, so you should not turn it off (well obviously!) but specifically not turn it off at night because that is when it does its EPG update. But that may not have been the FOX but some other Humax product.
It would be crap software if it did not regularly update the EPG. But then you cannot auto record what you don't know about

Recording a series should work... I have some 60+ episodes of that abandoned engineering projects series and none seem to be missing. So maybe for a series there is some other mechanism.
Now, if one is talking about recording say every programme with "Apollo" in the name, that is a different thing. But few people will be doing that. Maybe the CF can do it.
What does Disable OTA do, given that there have not been any factory firmware updates for 10? years?
This is what google says:
Based on user experiences and troubleshooting for the Humax HDR-FOX T2 (Freeview) and related Foxsat HDR (Freesat) models, a series recording can fail if the device is left on a different channel for a very long time, though this is usually due to signal or EPG update issues rather than a direct punishment for not changing channels.
Here is the breakdown of why this happens and how to prevent it:
Why It Fails
- EPG Update Failures: The Humax PVR requires regular updates from the broadcasters to keep the Electronic Programme Guide (EPG) accurate. If the box is left on a channel that doesn't carry updated metadata (or no channel at all for a long time), it may not pick up the updated time/channel information for the next episode in a series.
- "Unable to Track Program" Error: If the series link data changes (e.g., the show moves to a different day or time) and the box hasn't updated its EPG, the series link fails.
- Multiplex Limitations: The HDR-FOX T2 has two tuners. If you are recording two things, it cannot tune to a third to update its schedule.
The Solution
- Leave on a Main Channel: When putting the box into standby, it is recommended to leave it tuned to a major channel (like BBC 1 or ITV).
and I do get that, if some TV channels do not carry the EPG and you left it on that channel for ages. The Humax should re-tune itself briefly to pick up the EPG but evidently it does not. So what is needed is a background task which selects a channel with EPG. Funny thing: in the morning I keep finding a channel like 250 tuned in, with nothing on it, and I've only just realised this!