Request number wont be attached to the incident when you submit the catalog item through the create request UI action.
Catalog Item has a field 'Use Cart Layout' which is false on the item (New Assignment Group). If that is false it goes through a different macro (catalog_cart_default).
Problem exists in catalog_cart_default macro.
- Go to Catalog Item where you are seeing this issue.
- Click on configure "Form layout" and add the "Use cart layout" field to the form view.
- Set 'Use Cart Layout' field value to True.
- Navigate to the relevant Catalog Item.
- 'Use Cart Layout' field is not on the form by default. Add it.
- Check (true) the field.