422 Unprocessable Content when adding Bundle with Expand to cart

Topic summary

Intermittent 422 Unprocessable Content errors when adding Shopify customized bundle products to cart. Storefront messages include: “All 0 {product name} are in your cart.” and “The {product name} cannot be added to cart.” In some cases the bundle is actually added (confirmed by Functions logs), but the UI returns an error.

Behavior and scope:

  • Not reliably reproducible; once triggered, persists for that product until /cart/clear, then works again.
  • Does not affect other items in the cart at the same time.
  • Occurs across themes (Dawn, Crave, Pipeline) and multiple merchants; also reproduced following Shopify’s tutorial.
  • Checkout may show “Inventory issues – bundled item is sold out.”

Attempts/workarounds:

  • Inventory adjustments and setting inventory policy to CONTINUE did not help.
  • Sample payloads and theme code (application/x-www-form-urlencoded POST to /cart/add.js) provided; code snippets are central for debugging.

Shopify status:

  • Acknowledged by staff; suspected link to a recent rollout.
  • Escalated from Functions team to Cart team; investigation ongoing, no fix or ETA shared.

Impact and state:

  • Blocks adding custom bundles in some live stores, affecting checkout migration timelines.
  • Issue remains unresolved; awaiting root cause and fix from Shopify.
Summarized with AI on December 11. AI used: gpt-5.

Hi! I’m following along the customized bundles tutorial and get the same error. I’ve created the bundle product along with the components.

If I add the bundle product to cart I get : 422 “The bundle product ‘{product_name}’ cannot be added to the cart.”

Subsequent attempts result to: 422 “All 0 {product_name} are in the cart”

If I then add a regular product to cart and attempt checkout, I get “Inventory issues - my bundled item is sold out” on the checkout page.

Just curious if I’m doing something wrong or if it’s an issue with the functions api.

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