Service Portal Service Catalog categories and their subcategories do not display when there is no item on the category level.
Steps to Reproduce
Create a catalog category with no items associated to it.
Create a subcategory in that category and associate items to it.
View the category or a list of categories including yours in the standard Service Catalog.
Note that Category (empty) and subcategories (not empty) display.
View the category or a list of categories including yours in the Service Portal Catalog.
Note that the Category does not display and neither do subcategories.
There is no known workaround for this issue. Review the Fixed In field to determine which versions have a permanent fix.
Related Problem: PRB715696