Found what looks like a bug - and it's very irritating!
I have a Netgear SC101 NAS device (two of them actually), and deleting folders with files in them appears to work (the folder disappears from the list), but if you refresh, it reappears - the delete has not actually done anything!
You have to delete the files first, then delete the empty folder.
I just upgraded to 8.2.2.5, but NAS is still not working when deleting folders. Deleting empty folders works OK, but if there is a file inside, it comes back after a refresh.