Showtime Anytime issue with iOS 16 and tvOS 16

I have a Spectrum TV subscription that includes Showtime (and HBO, but no problem with that). Accordingly, I need to use the Showtime Anytime app if I want to view content outside of the Spectrum TV app. Prior to iOS 16 and tvOS 16 this worked just fine. But suddenly, any show on Showtime defaults to using Apple's Showtime channel option rather than the Showtime Anytime app. If I start watching a show in Showtime Anytime, it will appear in the Up Next section of the Apple TV app, but as a Showtime channel show, not Showtime Anytime. If I get details on the show, Showtime Anytime is in the list of options for playback, just not the default option. I have reported this through Apple Feedback, and ask that anyone else experiencing this do the same. If not fixed, I assume that iPadOS 16 will have the same flaw.