Why are some of my bundle not breaking down into line items in orders?

There are two main reasons why products in a bundle do not appear when the order is created.

1. If the order created is not editable from Shopify due to various reasons, the line items will not get added to the current order. Instead, a new associated $0 order is created with the bundle references and bundle items. 

2. If the added products in a bundle have a subscription or selling plan associated with them, you want to ensure that the option for Only allow purchase of this product as a subscription is unchecked.

To disable selling of the product only in subscription:

1. Click on all the products in a bundle from the Simple Bundles page
2. Scroll down the Subscriptions section
3. Uncheck the Only allow purchase of this product as a subscription option
4. Save the changes on the product variant