Hello @foobnix!
Big fan of Librera and patreon supporter for a while now!
Running 9.2.40-fdroid on a
Supernote Nomad A6 X2 Chauvet 3.26.40
I have most of my library on an SD Card setup in Library Settings > Folders to Scan working great.
I want another library available on the local drive. I added it to the Folders tab and can view it there. It's listed in the Folder dropdown as "primary

ocument/calibre". However when I try to add it to Folders to Scan I get the error "Incorrect value".
Any thoughts?
Cheers!