Explain the Series X|S version?

I got Ultiamate Edition and yesterday I could install "Control Ultimate Edition - Xbox Series X" which is a 272 MB game optimised for Series. I have it installed alongside the normal game and when I try to launch Series one it sends me to the store page of itself.

Update: Turns out the base game was installed on an external hard drive, moved it to the SSD with the tiny game and it still brings me to the store page.