When reordering with drag/drop it looses parent page

Hi,
i registered a custom post type with ‘hierarchical’ => true and ‘supports’ => array(‘page-attributes’).
Dragging works.

But if i assign a parent page other than the main page (f.ex with “Quick Edit”) and then drag that item to another position, it looses the parent page and gets “Main Page” assigned.

Thanks for looking into it.