wrong filter link in relate parent field

task=records.filter&filter_name[0]=filter_type&filter_name[1]=filter_&filter_val[0]=3&filter_val[1]=29

field id isn't there

Link type is set to "as prefiltered list"

Is it a bug or did i miss a setting?

Edit: cobaltrelate.php line 467

$url .= '&filter_name[1]=filter_'.$this->field_key;

should it be?

$url .= '&filter_name[1]=filter_'.($this->type == 'child' ? $this->id : $this->params->get('params.child_field'));