OS6.2 on RN516, SMB sync fail Goodreader

My RN516 runs 6.2 just fine, but I recently noticed that when I sync folders with SMB in my iPad Goodreader I get an error message "invalid response from server" and code 15330. It happens on all my shares when files are added or changed. Removing files is ok and they are removed, but when you re-add them, Goodreader says it got an invalid response.

I have an old Ultra NAS as backup and running OS4 still that doesn't give me any trouble syncing, but out of the blue my RN516 on OS6.2 does...

I'm 99% sure though it started after I updated to 6.2... Any thoughts?