Windows recursive import: Collection-Folders empty

Very latest DR 5.0.0 for Windows.

I’ve imported 132k+ images, recursively, from NAS SMB, UNC named like:
\server.domain\share\path

The import ran the whole night; LAN 1Gbps, no problems - all my pictures are visible as expected, I can select “film roll” and see all the “last-folder-part” “film-rolls”, I can even sort on “full path” and it works as expected, so the db-information+index is surely in place.

But when I select Collections → Folder, I see no folders at all: the list is not populated, as I’m used under Linux. It’s just empty.

My wild guess is, it relates more with rendering the “\” prefix in UI than something in the the DB, as the folder-information is usable even when I enter a search pattern into the textbox beside the “folder” dropdown.

I’ve researched and found a few topics mentioning a BUG in an older version of DT - but I have the very latest one, 5.0.0 currently.

I’ve tried to remove the darktablerc file, didn’t help. I’ve then tried to delete the AppData\Local\darktable folder and reimport again, didn’t help either.

Pls, w/out debugging the sources on my side, anybody knows how to fix this?

TY