I've created quite a few sites with mobile variants, and they all display the mobile variant on my mobile phone regardless of phone orientation (vertical or horizontal). One, however, (and only this one) displays the mobile variant when vertical, and the main site when horizontal. I'm using a Note 20 Ultra, but the other sites are mobile, whichever orientation, on this phone. Only the one site seems go back-and-forth when you spin the phone.

https://www.kungfushihtzugrooming.com

Any ideas why?