This is a problem that I also experienced when I had the Sky Sports add-on as a customer with TalkTalk.
I have NowTV for the Sky Sports package which covers a lot that BT Sport does not.
One of these is Rugby League which Sky take from Australia's National Rugby League as well as Europe. Obviously the time difference can be a problem sometimes with games spread across a 4 day period so that Australians can see every match. The early afternoon starts [Australian Eastern Standard Time or New Zealand Daylight Time] usually mean I need to record and that was why I grabbed the add-on with BT.
The common problem is that the program is not recorded. What I get is a recording lasting 1 hour 54 minutes and 57 seconds whether, or not, the game and program have completed.
The recordings start close to kick-off now and not the beginning of the program as transmitted by Fox League. But the length of recording stays the same and does not follow the game. The previously suggested solution on TalkTalk forum was to record programs following the rugby league slot. Had as many as 4 recordings to see a complete game. Today I got to 62 minutes of the game and the recording ended. And then I realised I had not prepared as usual with additional recordings.
My fault. I can record the series but cannot be sure each game is followed by an identical program every time and it never is.
What I have never understood is why this happens. I have had it with recordings on BBC and switched to iplayer to see the end. BBC radio music recordings have ended before the last record has been completed. I cannot see how the time of the slot is not pre-determined but in the case of a rugby league broadcast that is ridiculous because the length of a game is not determined by a clock.
Has anyone come across of a means of manipulating the length of a recording on the BT box? Just like video tape did.
Sadly there is no way around this, and is something none of the Youview related platforms have ever cared to rectify in all the years they have been in existence. Youview boxes (whether retail/BT/TalkTalk) fall down very badly when it comes to how they handle recordings. I find a 'rival' company to be much better when it comes to the recording functionality. It's not just Now TV related channels, as you have found out with your experience of setting BBC recordings. All channels are handled the same, whereby Youview boxes stick to the epg times when handling recordings 🙄