ADSelfService Plus: Imposible to LOG IN if "User must change password at next logon" is enabled

Application:

ADSelfService Plus

Version: 6.5.1.5 → 6.5.1.9 (Post-upgrade)

Issue Description:

Following the recent critical upgrade to version 6.5.1.9, we’ve observed a change in behaviour affecting user Log in on the App.

In our organization, when a password is reset in Active Directory, we typically enable the “User must change password at next logon” option. Users are then instructed to log in to the ADSelfService application to change their password and complete enrolment.

However, after the upgrade, the following issue occurs:

If the password is reset with “User must change password at next logon” enabled, the user receives the error:
“Invalid loginName/password. Please try again.”
when attempting to log in to the ADSelfService app.
If then the “User must change password at next logon” flag is removed (without even resetting the password again), the user can log in to the app without any issues.

Additional Information:

This behaviour is consistent across multiple domains and affects all users.
We manage approximately 25,000 users across 10 independent domains.
The issue has been confirmed by end-user reports and internal reproduction.

Impact:

This is a critical issue for us, as the “User must change password at next logon” option is standard practice for all password resets in our environment.

Request for Feedback:

Has anyone else experienced this issue or reported similar behaviour after upgrading to version 6.5.1.9?