A fix is now available for the User Profile Disk issue where a UPD does not correctly unmount at logoff causing temporarily profiles!
"...Addressed issue where the user profile disk (UPD) does not get unmounted when a user logs off. Therefore, users get temporary profiles and are not able to work with their own profiles during their next logon. The Event ID 20491 with a description of “Remote Desktop Services could not disconnect a user disk for the user account with a SID of <SID>. The error code is 0xAA.93” will be logged..."
The update is part of the October 2016 Preview of Monthly Quality Rollup for Windows 8.1 and Windows Server 2012 R2