FCPX NAS/Server issue, Aliases to proxy files changing - anyone had this?

Hi. I have a QNAP NAS, when I download a FCPX library over a network, (via a browser), my Mac doesn't see the aliases in the Original Media folder for the proxy files, it sees them as normal files so the proxies won't like when I open the library and I get a 'Modified File' warning. But if I download from the NAS as a Connected Drive it works fine. Please see screenshot. Does anyone know why this is happening? Thanks.