diff --git a/lib/outputcomponents.php b/lib/outputcomponents.php
index e08b3d3ab97..b6277cb1cf8 100644
--- a/lib/outputcomponents.php
+++ b/lib/outputcomponents.php
@@ -4682,6 +4682,12 @@ class action_menu_link extends action_link implements renderable {
      */
     public $actionmenu = null;
 
+    /**
+     * The number of instances of this action menu link (and its subclasses).
+     * @var int
+     */
+    protected static $instance = 1;
+
     /**
      * Constructs the object.
      *
@@ -4705,10 +4711,8 @@ class action_menu_link extends action_link implements renderable {
      * @return stdClass
      */
     public function export_for_template(renderer_base $output) {
-        static $instance = 1;
-
         $data = parent::export_for_template($output);
-        $data->instance = $instance++;
+        $data->instance = self::$instance++;
 
         // Ignore what the parent did with the attributes, except for ID and class.
         $data->attributes = [];