Maybe the GPO gets applied without Network Access and so they cant get the changes(Networkdrive mapping)

Has this occured on the same Person?

There is a GPO Policy to Wait for Network, but ensure it is only active on Internal Domain Clients, and not on Mobile/Laptop Computers

Check this https://technet.microsoft.com/en-us/library/gg486839.aspx

Maybe the GPO gets applied without Network Access and so they cant get the changes(Networkdrive mapping)

Has this occured on the same Person?

There is a GPO Policy to Wait for Network, but ensure it is only active on Internal Domain Clients, and not on Mobile/Laptop Computers

Check this https://technet.microsoft.com/en-us/library/gg486839.aspx

Without this Settings, Clients maybe Authenticate with Local Credential Store but the Network stack don't finished loading.

We got this Problem on our Site, but its a Computer/Network Driver issue that the initializeing/loading of the Networkdrivers/Stack are taking so long.