Issue Changing passwords for Protected Directory Users not working

[jtroher]

We have Plesk Onyx (17.0.17 MU #29) running on a Windows 2016 server. We've come across an issue where when a password for a user of a Protected Directory is changed, the new password doesn't work. The old one continues to work. If the user is completely removed and added back in with a new password it works fine, but then if that password is changed it doesn't go through either. It doesn't give any errors, and acts as if it worked but it doesn't. Anyone have an ideas on this?