Problem with Single Sign On (SSO) after AD Password Change

I have an APM portal page in front of Citrix Storefront for external users.

 

I have SSO configured and it is working well, automatically signing into Storefront with the AD password captured in the variable at initial login.

 

The problem comes after someone changes their password because it has expired. The user gets the change password prompt, does so and then the SSO seems to use their original password instead of the new one to log into Storefront.

 

I have confirmed that the password change is being replicated immediately. Changing the AD password with Users and Computers and then instantly logging directly into Storefront with the new password works fine.

 

Is there another variable or some way of fixing this issue, or at the very least can I force the session to log out and start again?