Lightroom Classic Parent folders showing count '0' images

The parent folders in Lightroom show a photo count of '0' images and the names are greyed-out, while the subfolders each show the correct amount of images (and are white). This is only present on the folders on my NAS; the parent-folders on my laptop-SSD show the correct amount of images. When I click on a parent-folder the images are shown.

This happened after re-installing Windows.
Library > Show photo's in subfolders is checked.

Is my library broken somehow?