I did update the auth keys – both prior to (days ago) and after installing the beta. I purged the WPEngine cache.
I should mention that I have a custom login-form.php in a child theme – would that have anything to do with my issue? – I updated to include the changes – still does not work.
I was able to make the password change once, but I realized that was only because when I clicked the email link it opened in a browser which I was already logged in as under a different user (admin).