Symptom:
As of Patch 7 on ISE 1.2, not seen prior to Patch 7, Guest users created with Sponsor holding their credentials on AD cannot login.
Sometimes, they will be able to login, but their password change feature will print an error page or return to the login page.

Conditions:
The below need to match:
1- Sponsors logging in via AD to create guest users
2- Guest users being put into guest groups and "Awaiting initial Login"