I'm primarily a boxing fan and my son is a UFC fan. I noticed very quickly that the guide info is so sparse on these two sports that it is nearly impossible to set a series link that actually works well.
With UFC, there is so much repeats of nearly all the shows, that if I set a boolean search for it for just 'new' shows, it doesn't make a difference since the guide data doesn't know if most of them are new or not. It is not uncommon to see 10 or more UFC shows in a single day, the vast majority of them being incessant repeats.
Boxing is similar though not quite as bad and some boxing events are tagged as 'new' in the guide data, but many, especially for SNY, FS1&2 and some others are not tagged with much info at all.
A bit irritating!
Is this the same for some other sports? I don't know as I don't watch them often enough to do series links for them, instead opting to manually record them as I see them come along.