I wonder if this is what’s going on for that video:
3840x2160 is the consumer 4K resolution. It’s 100% normal and expected that 3840x2160 HEVC media is coded as 3840x2176 because of codec implementation details.
Moussa’s comment on the other thread is that the Xbox decoder is crabby.
This seems like a gigantic 
to me, but … I don’t have a Series X 
