Why Is Edit Access Granted for Transfers but Not Promotions?

A promotion is carried out for employee X, and their business unit is changed from A to B.
The approver has an area of responsibility that allows them to view employees in business unit B, but not in unit A. In this case, the approver receives the notification, but the Edit button is not visible.

A global transfer is then carried out for the same employee X, again changing their business unit from A to B.
The approver remains the same, with the same area of responsibility that allows visibility of employees in business unit B, but not in unit A. In this case, the approver receives the notification and the Edit button is visible. The notification can be edited.