Controlling access to synchronized emails

I am doing a trial of Dynamics CRM. There are two users: Admin and Employee

Admin is automatically syncing emails successfully to the CRM for chosen contacts. These contacts are not shared/visible to Employee.

If Employee navigates to All Activities, they can see the emails that have been synced from Admin. Clicking on the name of a recipient under "Regarding" yields the message "Access Is Denied". However Employee can click on the "Subject" of the email and view the email.

It's not clear to me why this is possible...