Update
This is a OneDrive issue, not a DEVONtech one.
OneDrive does not support tags on non-image files so when it syncs, it removes Finder tags from non-image files.
This is clearly visible behavior in the Finder after making a change to a file in OneDrive on a PC.
… still need to double-check the Mac behavior.\
And as expected… Finder tags are not synced nor preserved by OneDrive, even between Macs.
On a side note: Tagging files in the Finder also does not provoke a OneDrive sync.