Adjustments made in classic are not exported to CC. Lightroom CC makes virtual copies in Lightroom Classic.
Lightroom Classic: Made adjustments on all 3 pics. Manually added metadata into XMP file in Classic for pic A. Pics B & C untouched.
Lightroom CC: Opened and added folder containing 3 pics(A, B, & C). Adjustments were seen in Pic A (XMP Added pic), B & C had no adjustments added.
Reopened Lightroom Classic and 3 new virtual copies were automatically added into folder. Pic A had adjustments on both pics. B & C had 2 stacked pics, one with adjustments and one without.
Pics were added in LR Mobile - A had adjustments where B & C had none.
Synchronized Folder in Lightroom Classic - No changes noted in Lightroom CC.
This just started about a week ago. Any Idea which setting was changed or whats happening?
It is not advised to use both Lr CC and Lr Classic. There is no connection between the images on your drive that are imported to Lr Classic, and the images in the Cloud that are managed by Lr CC. The only images that maintain a connection are ones captured with Lr CC on a mobile device that are automatcally synced back to Lr Classic.
I've provided a full explanation of what I think the problem is, over at the official feedback site where the OP posted the same question: