Pending Worker Role is not removed when converted to Employee

We have role mappings assigned to Pending Workers and also to Employees.

The Pending worker has ONLY the Pending Worker Abstract Role and the Employee has the Employee Abstract role.

When we load the Pending worker, they correctly get the Pending Worker Role only.

When we CONVERT, they get the Employee Abstract Role added but the process does NOT remove the Pending Worker Role.

What are we missing? They should no longer have the Pending Worker Role.