Edit pages restrictions are applied automatically to all child pages. This is a default behaviour. Use ure_auto_access_child_pages filter to change it.
Use this code sample to switch off the automatic allowed/restricted pages list extension – do not include child pages into the pages list:

add_filter('ure_auto_access_child_pages', 'ure_do_not_include_child_pages', 10, 1);
function ure_do_not_include_child_pages($include_children) {
   $include_children = false;

   return $include_children;