For clarity...
Hmmm, AppleTV + channel on some Roku but not others
This would be clearer if written
"Hmmm, AppleTV + channel works on some Roku MODELS but not others"
I thought from the title of the thread that he had, say, a dozen mixed models of ROKU and a miscellaneous set of the dozen would not play the Apple TV +. It turns out that the situation is totally model-dependent. That's very different from miscellaneous.
It looks like Roku and Apple are not playing well with one another for some reason.