Why are users not receiving email notifications for new supplier self-registration?

Previously, any enterprise user with the Supplier/Customer Manager group assigned, either directly or indirectly through other groups, used to receive email notifications related to supplier self-registration.
Now, only the users who have the Supplier/Customer Manager group directly assigned to them will receive this email notification (A new supplier has self-registered).

Spend Visibility
Strategic Contracts
Strategic Sourcing
Supplier Information & Performance Management > SIPM Registration/Login