2FA not loading after login

I’m using WP2FA with UsersWP. Up until a week or two ago it was working fine, no issues. Now, users can login with their WP login, but the form hangs and does not continue to the 2FA entry. If the WP2FA plugin is disabled users can login with no issue.

Of note, this is specific to the UsersWP login form that opens in a lightbox across the site. I can go directly to my custom login page and when not opened in a lightbox the form does redirect to the generic wordpress 2FA entry page.

I’ve cleared the cache, disabled all plugins but UsersWP and WP2FA, bypassed Cloudflare temporarily. Same results.

WP Cerber is simply reporting a HTTP 500 error, but does show the user is logged in and then the session is immediately terminated. Only when logging in via the popup; using the custom login page works. The debug log shows:

[21-Apr-2022 11:40:31 UTC] PHP Warning:  Undefined property: WP2FA\WP2FA::$backupcodes in /var/www/themays.me/public_html/wp-content/additional-apps/userswp/includes/class-forms.php on line 1328
[21-Apr-2022 11:40:31 UTC] PHP Fatal error:  Uncaught Error: Call to a member function codes_remaining_for_user() on null in /var/www/themays.me/public_html/wp-content/additional-apps/userswp/includes/class-forms.php:1328
Stack trace:
#0 /var/www/themays.me/public_html/wp-content/additional-apps/userswp/includes/class-forms.php(1175): UsersWP_Forms->check_2fa()
#1 /var/www/themays.me/public_html/wp-includes/class-wp-hook.php(307): UsersWP_Forms->process_login()
#2 /var/www/themays.me/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#3 /var/www/themays.me/public_html/wp-includes/plugin.php(474): WP_Hook->do_action()
#4 /var/www/themays.me/public_html/wp-admin/admin-ajax.php(202): do_action()
#5 {main}
  thrown in /var/www/themays.me/public_html/wp-content/additional-apps/userswp/includes/class-forms.php on line 1328

I’ve tried tracking down the issue myself, but have very little experience with coding and have not had any luck fixing the problem.