Thanks - this is indeed a bug in Q2A 1.5 that shows up with certain URL formats. Please try changing the following in qa-app-format.php:
$fields['what_url']='?show='.qa_html($postid).'#'.qa_html($anchor);
... to ...
$fields['what_url']=qa_path_html(qa_request(), array('show' => $postid), null, null, qa_anchor($post['basetype'], $postid));
This fix will be rolled into Q2A 1.5.1.