When multiple changes are committed to the database, Designer allows to assign individual changes to a special change label. Expected behaviour would be that the change is not assigned to the label selected on top of the popup box.
But all changes are assigned to the general change label, regardless of what has been set as special change label. The special one is empty after the changes have been committed.
This will be fixed on a future release of the product. If you require this immediately corrected, please contact support for a hotfix referencing the defect ID 25845.