tomorrow we’ll rewrite our batch proxy exports to render frame by frame (though is is less efficient in generation), and test.
TO be more precise about the locking, here is what we see:
1/when a render is running on one node or more, windows explorer can read and copy to another location the vrmeshes.
windows explorer cannot delete or move the file stating that is in use ( which is true 
)
maya through gui cannot import the vrmeshes (freeze)
any other render seems to struggle to get acces to vrmeshes and waits.
2/ when render is finished or disabled, windows explorer can read, copy , moce delete the vrmeshes
maya can import vrmeshes
If we change the file rights so they are read-only (which possibly prevent to put a write lock), vray fails to load the vrmeshes ( like it requires a read-write access to the files).
I’ve tried to disable handling of locks on my file server ( which is hihgly unrecommended to prevent file corruption) and it changes nothing.
it behaves like both vray rendering and proxy/import/loading in gui requires more locking than expected ( we would expect a file read lock or something like that)
Rgds