Apple TV4K iTunes content is not HDR

I have an ATV4k that was working well until this week. This week I noticed that iTunes movies that are Dolby Vision/Dolby Atmos (e.g. 2001: A Space Odyssey, John Wick 2) are not streaming with the high quality video and audio. Interestingly, Dolby Vision/Dolby Atmos content from Netflix (e.g. Our Planet) on the same ATV4k box is streaming fine with full high quality. I'm also getting HDR streams from the Amazon Video app on the same ATV4k, HDMI cables, soundbar and TV. This is confirmed by the info button on the TV and the indicator lights on the soundbar that show the type of data (SDR vs HDR10 vs Dolby vision and Normal sound vs Dolby Atmos)

The fact that streams from sources (Netflix and Amazon) other than iTunes works fine seems to rule out my local/isp network speed (~200mbs down), hardware and cables between the ATV4k to the Vizio PQ65 TV with a Vizio Atmos enabled soundbar in the middle. Sometimes when starting a new iTunes movie, I can see it may be buffering with a message of "movie will start in x minutes", but then it usually starts in a few seconds, but at lower quality than I expect. Is there an issue with the iTunes servers that is delivery of content is being throttled to prevent high quality streaming? Anyone else seeing this?