Since you didn't list the name of the program, I can only guess what is going on. It probably was a joint production of PBS and ITV. It probably aired first on ITV, maybe even today 10/12/2022. Then as history is a guide, it will air on PBS about 6 months later.
Going to theTVDB.com will explain where it first aired and when. IMDb.com might help with if it aired anywhere after that. Going to Wikipedia and looking up the show would probably supply even more info.