Link field problems "The page slug is required"

i have link fields in my file blueprint for an image gallery, that should have the possibility to link to subpages to my “works” page. i don’t know why the problem comes up, but when i try to open up that section in the picker, i get the message: “The page slug is required”.

the works subpages are routed to be my.url/subpage instead of my.url/works/subpage, would that be an issue?

Does the issue go away if you comment the route?