If you are calling Rich Display files using BASIC authentication (start URL will contain /auth/ such as http://IP_ADDRESS:8080/profoundui/auth/start) the http server will not handle expired passwords. This is normal behavior:
You can however allow the user to change their password by directing them to this page http://IP_ADDRESS:8080/profoundui/changepass
If data area PROFOUNDUI/PUIPWDMG is set to '1' you can only call this page if the password has expired.
If data area PROFOUNDUI/PUIPWDMG is set to '2' you can go to this page to change the password at any time
You can customize this page by editing html page /www/profoundui/htdocs/profoundui/userdata/html/change_password.html. Make sure you keep a backup copy in case it is replaced with a product update.