I have several Windows 10 clients but have an issue with just one, it's on build 14955 but had the same issue on the previous pre-release also. Machine is a Windows Server 2008 R2 domain client.
When on the LAN the main user account (domain admin) can login to the machine fine but when disconnected from the LAN it presents incorrect password even though the password is known good. Domain name is home.local which definitely isn't resolving when disconnected.
This has me baffled.