It sounds like the website is probably trying to prevent users from saving their passwords. They usually do this by including a hidden text box on the website and tricking Firefox into thinking that's the text box that the password is saved in. Then, Firefox tries to save that as the password.

I would recommend trying to manually add or edit the password for that website using the Firefox password manager. See Manage your logins with the Firefox Password Manager for more information.

Hope this helps.

Some websites modify the login form via JavaScript when you submit the form to prevent browsers from storing login data or otherwise as a security measurement.

You can manually edit the password in Lockwise and create a login block exception to prevent Firefox asking to update the password each time you login.

• Options/Preferences -> Privacy & Security: Logins and Passwords
• https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins

See also:

• /questions/1308217 Update login info prompt fills in a bogus password