Word for Mac on NFS share thinks documents are read only

I have a strange issue with am Unraid server running NFS shares. Facts: * Running a fresh install of Word on a fresh Mac on a fresh Unraid server * Documents are on an NFS4 network share * The share and documents has all permissions: Read - Write - Execute * I can verify this by using "Get info" on a Word document and see that myself, mygroup and all users have Read and Write. I can also verify directly on server. Documents are 777 (rwx for all) * Ready only is not set on document (as seen from Mac get info) * Locked is not set on document (as seen from Mac get info) Symptoms: * When I open a document located on the share in Word on the Mac - it displays a message that the document is read only and only gives me the option do duplicate it. I can duplicate it fine and save to the network location, but when opening the duplicated document, I get the read only message again. * No other programs are behaving this way on the same share - Excel, Powerpoint etc works fine. I can even open a Word document in a text editor and are able to save it - so if it definitely not read only * If I create a new Word document and save it to this network share - I get the same behaviour - it gets read only * If I map the network share using samba (SMB) protocol instead of NFS, it works fine - issue is only with NFS (but I prefer NFS due to speed & reliability when there are many files) So somehow Word thinks that documents on the network share are read only - while they definitely not are read only. Any ideas?