UPDATE 1/15: We are releasing Windows 10 Insider Preview Build 18312.1007 (KB4487181) to Windows Insiders in the Fast ring with the following fixes:

We fixed an issue resulting in File Explorer unexpectedly having a lock on USBs when trying to safely eject them.
We fixed an issue resulting in frequent bugchecks (GSODs) in the last two flights, citing an error with bindflt.sys.
We fixed an issue where a password change can result in the next unlock hanging for AD users.