I have all my music on a Drobo nas mapped to a drive on my core and remote machines. Organized by Artist > Album > Track. Core is Win8.1, remote Win10. The mapped drive is setup as a watched folder. Initial import and adding albums to existing artists seems to be working as expected. If I add a new artist, Roon is not adding the files, I need to add that specific artist folder as a watched folder. It looks like the watched folder is identifying tracks in it’s initial folders, but not folders that are being added.
Just to be clear, you set the whole drive e.g. F:\ and not a sub folder. If so, try adding a sub folder like F:\test as a watched drive and copy an album or two into it.
" try adding a sunflower " don’t you love autocorrect 
GAK. I do hate auto correct although sometimes the results are priceless. 