Registration Code interferes with Password Change

I have installed Registration Code in the latest version of Drupal - it works for newly created accounts to get into Drupal, but when already registered users go to "My Account" and "edit" to change username or password, it is impossible to save the changes because an error message comes up which says "Invalid Registration Code" - so the Registration Code module is interfering with the regular functionality of a User being able to edit their username and password.

When I turn off the Registration Code module, this problem goes away. Note that even if I put the official Registration Code in the password box (same one used to create the account in the first place) - it will not work. So Registration Code Module is making it impossible for users to change passwords and save the changes.