Same question that James asked here:
https://social.technet.microsoft.com/Forums/en-US/7bc17e42-ea21-464e-9b71-6899f7edc61b/dfsr-random-files-disappearing-specifically-losing-all-permissions-and-ownership?forum=winserverfiles
This has happened 1/2 dozen times on a server that has finally had all the files moved into the DFS namespace around 2 months ago.
3 or 4 of those times have been to the same file.
A user will close the file, then no one can find it. They assume it's been deleted or something. However, when I look, I can see the file. When I try to look at the permissions, there are none and there is no owner. Once I assign an owner, I can manually assign permissions or I can go to the parent folder and apply inheritance. The file will then have the correct permissions.
Until it happen again.
The only similar occurrence that Google will find is the one referenced above. And I don't know how to message that fellow directly.