When you create a category and associate products to the category or change the category definition, you must run a Category Maintenance job. If you do not run category maintenance, the Sales rep may see incorrect hierarchy or totals on the cart page.
After making changes to the existing category definition you can run the Category Maintenance batch job only for changes rather than running for the entire definition. For example, if your category has 10 products and you added 5 more, you can run the Category Maintenance batch job only for the 5 additional products.
Refer to Running Maintenance Jobs in CPQ on Salesforce Administrator Guide.
You must run the Category Maintenance batch job after every CPQ version upgrade.