An issue may occur when local administrators attempt to modify delegated permissions from either user accounts, shared mailboxes or distribution lists. The delegated permissions are successfully modified in Exchange but not Active Directory. This can be observed by checking the permissions tab for the object which will still show the previous permission(s).
Latest update and guidance
This issue is being investigated under PRB0171899.
Local Admins can check user permissions under the Permissions tab. If a discrepancy is seen, then please raise a request with the NHSmail Helpdesk (firstname.lastname@example.org) informing the Helpdesk that delegate permissions have been removed but they are still visible under the permissions tab.