"Cannot change contents of folder-based gallery"

When I did an initial scan + generate for my collection in stash, my files were in a smattering of random folders from when they were downloaded. Now every image has been forced into a gallery with other random images. I have since moved all files into one large folder, deleted the original folders they were located within, re-scanned, and yet the galleries with the error in the title still persist. I have also disabled the option to create folder-based galleries by default too

How do I fix this?

If there are leftover folder-based galleries, these can be removed by a clean operation, or just delete them manually.