Whilst I bow to the expertise of others on this site, I’m convinced there’s something screwy about the completion state reporting of Remote Devices - and I suspect that’s what you’re seeing here.
If the PC’s view of its local folders says it’s Up to Date, but the Mac’s view of the PC as a Remote Device is different, then I suspect you don’t have anything amiss - just that the reporting is bad.
I’ve raised this before - Remote Device Sync Completion State - but I’ve not been able to find a reproducible test case yet. If this is what you’re seeing, then it’s good to know I’m not alone… 