I've tried looking it up but either places don't mention them at all, or simply list them without saying if it's a "season" or not. https://www.animenewsnetwork.com/encyclopedia/anime.php?id=23494&page=25 (and) https://en.wikipedia.org/wiki/Uma_Musume_Pretty_Derby#Umayon

Both the Special episodes and Season 2 appear to be the same thing with the same airdates, and Wikipedia refers to them as OVAs so they should probably stay in Special and someone needs to remove "season 2", perhaps?