Test the bundle once without a code, then apply the code to the same cart. This shows whether the problem is the bundle itself or the combination of promotions.
1. Compare the same checkout
Empty the cart and remove existing codes. Select one bundle offer and its variants.
Add it and check the products, quantities, and bundle discount at checkout.
Apply the additional code. Compare the discount labels and final total.
Keep the test consistent: use the same customer, country, and currency. Customer restrictions and minimum spend can change a code’s eligibility.
2. Check the promotion settings
Shopify → Discounts
The code’s combination settings, products, customers, dates, and minimum requirements.
Sternify offer
Percentage, fixed reduction, or fixed price; the selected variant; and any market-specific values available in your editor.
Checkout
Which discount actually applied to the items in this cart.
Open the code in Shopify → Discounts, find Combinations, then open its edit control. Check the relevant product, order or shipping category for both promotions. The unchecked boxes shown here are an example, not recommended settings; eligibility rules still apply.
Shopify treats product, order, and shipping discounts differently. Both promotions must be eligible to combine; multiple product discounts on the same item have extra restrictions. If they cannot combine, Shopify can select the better eligible result. See Shopify’s current combination rules.
Read the result
Bundle fails without a code
Check active status and the exact items and quantities in the offer.
Bundle works until the code is added
Check combination and code-eligibility settings.
Only the struck-through price differs
Check the compare-at display. It is a reference, not an extra discount.
If the result is still unclear, send support the offer, code, market, and before/after checkout screenshots with your expected total.