I got this notice on the edit page of a content :
Notice : Undefined index: #collapsed dans relatedlinks_form_alter() (ligne 383 dans***/sites/all/modules/relatedlinks/relatedlinks.module).

which is :
$form['relatedlinks_fieldset']['#collapsed'] = $form['relatedlinks_fieldset']['#collapsed'] && empty($track->keywords);

maybe something like that may fix that :
$form['relatedlinks_fieldset']['#collapsed'] = isset($form['relatedlinks_fieldset']['#collapsed'])?$form['relatedlinks_fieldset']['#collapsed']:1 && empty($track->keywords);