source/blender/windowmanager/intern/wm_event_system.cc

@@ -239,6 +239,11 @@ static void wm_event_free_last_handled(wmWindow *win, wmEvent *event)
   if (win->event_last_handled) {
     wm_event_free(win->event_last_handled);
   }
+
+  /* While not essential, these values are undefined, as the event is no longer in a list
+   * clear the linked-list pointers to avoid any confusion. */
+  event->next = event->prev = nullptr;
+
   /* Don't store custom data in the last handled event as we don't have control how long this event
    * will be stored and the referenced data may become invalid (also it's not needed currently). */
   wm_event_custom_free(event);