Wow.
Yes, Autosync was highlighted, and I assume that means On.
The first screenshot did not have these buttons highlighted or active.
The second s the button became active (sync metadata) but not highlighted
The third screen it became (without any action on my part) active AND
highlighted as "Autosync."
And it remained this way throughout the rest of the session.
As I am understanding this now, the main "Sync" button opens a menu where
the user can select what items to sync among the image group; the
"slide-switch" on the side of the button enables "Autosync" syncing
everything (?) or syncing according to the Syns Settings status.
Am I correct that this "Sync" relates only to the images in the group and
is unrelated to "syncing" folders, etc.?
What would be a recommendation as to how to generally have this option set?AutoSync ON is a mode whereby whatever you do applies immediately across all selected images, not only to the active image. So for as long as the switch is set as in my screenshot, you have to be continually careful about what you have selected, since bulk changes may be intended (powerful) or not intended (dangerous). It's incompatible with having a set of images selected and Picking just one of those; since all will be Picked.
I suppose if these images were stacked you could instead promote the chosen image to be head of the stack and Autosync being ON would probably not interfere with that. I'd advise turning AutoSync off unless / until you might decide to adopt it routinely, and hence to fully learn the needed awareness.
When AutoSync is OFF, whatever you do applies only to the active image. To then repeat this same work onto other images, a further action would be needed after the fact: 'copy/paste settings'', repeat 'previous' image settings, or using the Sync button at lower right.
You are right, the Sync and the Autosync features referred to in this reply have got nothing to do with synchronising local images, nor their edits, with the online Creative Cloud ecosystem - nor, with syncing the contents of a Folder.