Information
Network File System (NFS) is one of the most popular distributed file system protocols that allows a client computer to access files on shared storage over the network. NFS version 4 (NFSv4) is an improved version of NFS protocol versions 2 and 3.
Solution
Turn on the option that allows root to access files with ACLs even if the ACLs would not allow access to the mapped Windows user.
Additional information: http://media.netapp.com/documents/TR-3580.pdf