Hi,
Thank you for the additional details provided by email. It helped to found a reason.
URE restricts editing of all post types, by default, including ‘attachment’ type. So if you allowed to user to edit pages with ID 2, 3, only this ID will be available for editing. But media library items attached to these pages are not edit to the list of allowed for editing IDs automatically. I will add this feature with the next update – in September, 2017.
Currently you can exclude ‘attachment’ post type from ‘editing restrictions’ as a workaround: https://www.role-editor.com/documentation/hooks/ure_restrict_edit_post_type/
