diff --git a/auth/oauth2/classes/auth.php b/auth/oauth2/classes/auth.php
index b8023216fb1..c591d6528af 100644
--- a/auth/oauth2/classes/auth.php
+++ b/auth/oauth2/classes/auth.php
@@ -63,7 +63,6 @@ class auth extends \auth_plugin_base {
     public function __construct() {
         $this->authtype = 'oauth2';
         $this->config = get_config('auth_oauth2');
-        $this->customfields = $this->get_custom_user_profile_fields();
     }
 
     /**
@@ -310,7 +309,7 @@ class auth extends \auth_plugin_base {
             return $userdata;
         }
 
-        $allfields = array_merge($this->userfields, $this->customfields);
+        $allfields = array_merge($this->userfields, $this->get_custom_user_profile_fields());
 
         // Go through each field from the external data.
         foreach ($externaldata as $fieldname => $value) {