Putting a couple of items together, perhaps 8TR addition means C28 colour doesn't support some aspect of ZDY (Driving Assistant Professional) functionality. I believe from earlier posts that in earlier versions of G05 X5 (late 2018 and early 2019 production dates), there was another colour that limited driving automation functionality for some reason (Sunstone) — perhaps C28 colour has the same issue?
Here is a thread discussing Sunstone and lack of ACC:
https://g05.bimmerpost.com/forums/sh....php?t=1598246