There is a new registry key, DisableAADWAM, which replaces DisableADALatopWAMOverride in newer builds of Office.
See if this helps
[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity]
“DisableAADWAM”=dword:00000001
We highly recommend deleting the reg key once the fix is out from Microsoft.