I suspect I already know the answer to this, but I’ll throw it out there anyway, just in case there’s a straightforward answer!
I see the Modified Time of folders is currently not synced across systems. Whilst this might not be an issue in many situations, I just came across a concern from one user where they were convinced the latest version of their document had not synced because the Modified Time was not up to date.
It turns out the document was actually a macOS package - a collection of folders and files masquerading as a single file. As the updated document content was buried deep inside the package (and, indeed, had synced correctly with the correct Modified Time), the Modified Time of the top level of the package was not updated - and consequently did not appear to be updated to the end user.
Is it a conscious decision not to sync the Modified Time of folders, or is it just too complex to do for such a niche requirement?