after hours looking debugging a problem I found the following bug:
quicktabs is not using the drupal mechanism to prevent duplicated HTML IDs (there's an AJAX option to pass ajax_html_ids on the AJAX request).
Can be found in ajax.js around line 290.
So when I load a tab per AJAX it is not passing the already existing ids, so that drupal can modifiy the ids.
The drupal_html_id function may also help!
Can somebody fix this or give me a hint, where I can fix it?! Thanks!