SSO login broken

Stacktrace on main.ci.stackspin.net:

[12-Jan-2022 07:51:59 UTC] PHP Fatal error:  Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array, string given in /var/www/html/wp-includes/additional_functions.php:5
Stack trace:
#0 /var/www/html/wp-includes/additional_functions.php(5): in_array('admin', '')
#1 /var/www/html/wp-includes/class-wp-hook.php(303): {closure}(Object(WP_User), Array)
#2 /var/www/html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array)
#3 /var/www/html/wp-includes/plugin.php(470): WP_Hook->do_action(Array)
#4 /var/www/wp-content-mount/plugins/daggerhart-openid-connect-generic/includes/openid-connect-generic-client-wrapper.php(524): do_action('openid-connect-...', Object(WP_User), Array)
#5 /var/www/html/wp-includes/class-wp-hook.php(303): OpenID_Connect_Generic_Client_Wrapper->authentication_request_callback('')
#6 /var/www/html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array)
#7 /var/www/html/wp-includes/plugin.php(470): WP_Hook->do_action(Array)
#8 /var/www/html/wp-admin/admin-ajax.php(202): do_action('wp_ajax_nopriv_...')
#9 {main}
  thrown in /var/www/html/wp-includes/additional_functions.php on line 5