So we migrated our fileshare to a DFS namespace and we started facing a lot of problems. One of the most annoying one was, no matter how we trust the source, the powershell scripts from the DFS namspaces were not able to run, as they give warning.
Interestingly, problem was that the FQDN of the DFS namespace is considered as an internet location by windows, causing it to not trust the location. This can be fixed by editing the local group policy.
Group policy editor -Computer configuration- Administrative templates – Windows components -Internet Explorer – Internet Control Panel – Security Page – Site to Zone Assignment List.