Component ID, Abbreviations not working

Project settings - Component ID Format I have the value set to use Subcategory/Abbreviation

If I create a Category/Sub Category/Abbreviation from the Control Panel/Catalog/Categories area; then assign a product to that Category, the Component ID ignores the Abbreviation and instead uses the Subcategory Name.

If I create a new Category/Subcategory from the Product Explorer, this then uses the Abbreviation correctly for a component ID.