SLA alert when overdue

Dear Experts,

i am checking the "Alert when overdue" of SLA's milestones.

If a ticket is created in the system and automatically assigned to an employee using Employee Work Distribution rule, then the alert is sent to the assigned employee.

Instead, if a ticket is assigned only to an Org Unit via Organizational Work Distribution, no employee is alerted. I thought that the manager would be notified, but not.

Is this an issue of the system or what?

Thank you