Final update.
After continuing to go back and forth for another couple of months, Apple customer service sent me this message:
Our team let us know that the iPad registers on our end as a high peak bit rate device, which would explain the movies appearing in 4K when it was tested out then.
The Roku displays as low peak bit rate device, which means that there are times when the device may be limited in processing high-quality video or large data transfers. This can reduce video quality and even cause buffering.
Thank you for all of the testing and the information that you’ve provided.
All of this conveniently ignores everything I reported to them. What a waste of time their customer support is -- yet another reason to keep avoiding Apple products. Clearly, @atc98092 , you were right when you said:
Personally, I think this is another case of a provider "crippling" the performance of a competing device. We know for a fact that Apple will stream videos at a higher bitrate (possibly higher quality) to an Apple TV device over other devices. Similar to Google taking functions out of their app/channel for Roku devices that are available on Chromecast devices. And Amazon has some things that just work "better" on a Fire TV.
