It's the responsibility of each broadcaster to set the Series Links. A few years ago I had a similar issue with Come Dine With Me on Channel 4, they had every episode linked irrespective of what Series it's part of. I was doing a bit of testing for Sky at the time and it was Sky who told me that it was the responsibility of each broadcaster, but as a favour Sky pointed the error out to C4 and it was fixed.
My Freesat box has just recorded a repeat of Yellowstone on Paramount, all you can do is monitor your scheduled recordings, deleting the extra ones on a BT Box will delete all scheduled recordings of that Series.
I would recommend downloading the BT TV app and pair it to the box. Use the app to monitor the scheduled recordings because it shows every recording for the next 7 days, whereas the box will only show the next scheduled recording. Using the app will help you notice future clashes that may occur due to these unwanted extra recordings.
BT would only be responsible for their own output such as Moto GP, they aren't that good at doing it either and nor were Sky with their F1.