EntityMalformedException with two registrations of same product

How to reproduce:

1. Product display node is set to not "Attempt to combine like products on the same line item in the cart."
2. Add registration product to the cart
3. Add a second of the same registration to the cart (two lines with same product in cart - good
4. Checkout and enter registration
5. Error occurs - EntityMalformedException: Missing bundle property on entity of type registration. in entity_extract_ids() (line 7879 of common.inc).

I need to have two different line items so each line item could have a different price. In our case a child registration is less than an adult registration.

With devel and krumo backtrace enabled I am now seeing two notices before the error:

Notice: Undefined index: 1767prod-2051066620-reg-0 in commerce_registration_information_checkout_form_submit() (line 305 of commerce_registration/includes/commerce_registration.checkout_pane.inc).

Notice: Undefined index: 1767prod-2051066620-reg-0 in commerce_registration_information_checkout_form_submit() (line 324 of commerce_registration/includes/commerce_registration.checkout_pane.inc).