It's a old problem I have, just trying, if I can make it work, It never did. The color class label in PM 6.0, build 7285 but also 2026.6, build 9175 do not show of
in ACR 18.70.2743. I think I tried everything. Star rating is working, the XMP Files show the right color label, but it does not in ACR. I use photoshop in the german version.
Could that be a problem?