I have had this happen, and as others say it is almost certainly the broadcaster getting the metadata wrong in the EPG. As well as programmes with breaks in the middle it sometimes happens when two episodes show recorded in a row – e.g. the BBC foreign drama slot on BBC4, I suspect for a similar reason.

I have however found that there is a relatively easy way to set the other missing part to record without the full manual entry by time. Just go to the “guide”, have the cursor in the bit not set to record and hit the record button (the red box on the remote). It will appear when recorded as a different entry in the recorded listings not part of the series, but that is much less worse than just missing the recording. Of course that still means you have to notice when it happens.

If anyone from Humax is watching this thread, something that would help, would be an easy option to from the box send a notification to the broadcaster of the problem. I have found that they generally react pretty well to be told such things – but the mechanism is cumbersome (go tot their website, hunt for “contact us” of the right sort, fill in form or send email explaining…), a few clicks on the remote to report incorrect metadata would be easier for users, and I suspect appreciated by broadcasters so they can fix things before the event, not after a torrent of complaints for a missed recording (although I bet a lot of broadcaster customer service teams just blame the box manufacturer).