User Permission based on Hierarchy

hello . is anyone facing some kind of issue with hierarchy permission . I have a lot of employees in my company . sometimes the permission baes on hierarchy (reports to field ) is incorrect . the manager sometimes can see his employees bellow him and sometimes not . there is not actual error , it just sometimes work sometimes not .

Please check this
https://docs.erpnext.com/docs/user/manual/en/user-permissions#212-hide-descendants