You have a Price Rule on before calculate that updates SBQQ__ListPrice__c using a formula which is something like: SBQQ__OriginalPrice__c * (SBQQ__Quantity__c *0.01). A formula that changes the list price based on quantity. You add a bundle product containing an option that is of type “Component” and save the configuration. The bundle product has a zero price. Component type options have their quantity calculated based on the parent’s quantity. It brings you out to the Line Editor. Things look good. You change the quantity to 50,000. Things don’t look good. Why didn’t the Price Rule update SBQQ__ListPrice__c of the child to the new price??
Component Option quantities get calculated between before calculate and on calculate. Your price rule doesn’t know about the new option quantity until on calculate.
Similarly, the Original Quantity (SBQQ__BundledQuantity__c) also gets calculated between before calculate and on calculate.
The optimal solution here would be to move the rule from before calculate to on calculate and done!