When VFS full_audit is activated the server doesn't allow users to write changes in any file.
The log vfs:10 shows:
Jan 12 22:22:00 loginserver smbd_audit: aaaa.bbbb|192.168.23.10|get_real_filename|fail (Operation not supported)|/Novo Documento de Texto.txt->(null)
Jan 12 22:22:00 loginserver smbd_audit: aaaa.bbbb|192.168.23.10|fchmod_acl|fail (No data available)|Novo Documento de Texto.txt|100764
Very likely a duplicate of bug 7326, please try the patch from there.
*** This bug has been marked as a duplicate of bug 7326 ***