When there are more than 1000 records in the [cmdb_ci_appl] table, the Blueprint catalog item loading is very slow. Disabling the CI Application field improves performance, because the blueprint has the Application variable with default ApplicationPool reference.

1. Fill the cmdb_ci_appl table with sufficient data (> 100kb)
2. Create a basic Blueprint Catalog Item with an Application variable/field.
3. Publish the item.
Note the blueprint catalog item loading takes 5-10 minutes because of the drop down menu rendering.

The workaround consists in creating a custom pool filter that restricts the list of possible Applications to ideally less than 100.

Ref. example:

https://docs.servicenow.com/bundle/london-it-operations-management/page/product/cloud-management-v2/concept/use-case-resource-pool.html

The alternative workaround would be to make the affected catalog item variable 'Reference' to 'cmdb_ci_appl'.