On scruffywiki I'd like to mass delete all files prefaced by "Cgs". There are hundreds there. In Special:Nuke I choose options namespace: File and Max number 500. It only displays about 31 files and after deleting the selected files click Delete more pages, repeat the above and it lists the same file names again.
Re-deleting previously deleted files is a known bug of Nuke - it doesn't matter if they were bulk uploaded or not. Once files have been deleted once, they continue to show up in Special:Nuke if you enter the username of the original uploader or leave that field blank... but it doesn't actually delete them again because it can't (it just says it did).
The one thing I can think of is that Nuke only deletes recently created pages, so it is possible that if the rest of the files were older than the ones that were already deleted, Nuke may not be able to retrieve them.