And again I ask, what about the other icon(s)? My entire desktop is on OneDrive, and sometimes all the icons on all my desktop files and folders are OK (ie, green circle with white checkmark inside), sometimes they all have the brown box, and sometimes (like right now) they all have 2 blue curved arrows arranged to make a circle. Many of my desktop items are folders, and I have never tried to look thru all of their contents in quick succession, but any time I HAVE looked into a folder, the contained files and subfolders have always had the green circle with the white checkmark, regardless of what icon is showing on the top-level folder (on the desktop). And anytime I have looked, my "OneDrive - Personal" icon in my "Taskbar corner" says "Up to date". Isn't there a list with explanations somewhere? Geesh!
(Full disclosure: Unlike some of the other reports on this thread, I have never seen an actual PROBLEM associated with these mystery icons ... so I'm a whiner. But still, maybe the mystery icons are telling me about a problem that I don't see. And in any case, THERE SHOULD BE A LIST! I looked for a list several months ago, but was unsuccessful, which is why I first got involved with this thread, hoping for quick resolution -- HAH!)
PS: An hour later (after the above), I noticed the case where NONE of the files and folders on my desktop have ANY icon attached to them. But inside the several folders on my desktop that I just how checked, ALL files and subfolders still have the green circle with white checkmark.