Cart Transform API wrong results - Price is coming 0 everywhere except on Checkout

Topic summary

A developer is experiencing inconsistent pricing behavior when implementing product bundles using Shopify’s Cart Transform API.

Core Issue:

  • One bundle displays correctly with proper pricing
  • Another bundle shows $0 price in cart calculations (both JavaScript and Liquid)
  • Checkout page displays the correct price, but all other contexts show incorrect/zero pricing

Technical Details:

  • Developer has followed official Shopify documentation
  • Function logs and cart JSON have been provided showing the discrepancy
  • The issue appears isolated to specific bundle configurations rather than all bundles

Current Status:

  • Developer suspects this may be a bug on Shopify’s platform side
  • Seeking validation or troubleshooting assistance
  • No responses or solutions have been posted yet

The attached code snippets show function input/output with bundle metadata, cart line items, and pricing calculations that demonstrate the zero-price anomaly.

Summarized with AI on November 5. AI used: claude-sonnet-4-5-20250929.

I am creating a few bundles for my client and it works fine for certain cases. I have followed everything from the Shopify docs and believe it has something wrong on Shopify’s side. Please check the attached function log and the resulted cart json.

One of the bundle is fine with 2 quantity and the other bundle is saying price zero which shouldn’t be zero. On Checkout page, it shows correct price but everywhere else, it calculates and displays wrong. I have checked both in JS and Liquid.

Here’s the function input and output:

{
  "shopId": 69771329753,
  "apiClientId": 155740569601,
  "payload": {
    "export": "run",
    "input": {
      "presentmentCurrencyRate": "1.0",
      "cart": {
        "lines": [
          {
            "id": "gid://shopify/CartLine/9955cb56-6d11-4b38-abde-59509030a1cb",
            "checkBundle": {
              "value": "Yes"
            },
            "merchandise": {
              "typename": "ProductVariant",
              "id": "gid://shopify/ProductVariant/45989319573721",
              "product": {
                "id": "gid://shopify/Product/8885528690905",
                "title": "5 Spice Ribs",
                "bundleDiscountPercentage": null,
                "bundleProducts": null
              }
            },
            "quantity": 2
          },
          {
            "id": "gid://shopify/CartLine/94921826-2d97-48d4-b7d8-52830caf4468",
            "checkBundle": {
              "value": "Yes"
            },
            "merchandise": {
              "typename": "ProductVariant",
              "id": "gid://shopify/ProductVariant/46008334647513",
              "product": {
                "id": "gid://shopify/Product/8885538390233",
                "title": "Bacon Wrapped Wagyu Tomahawk",
                "bundleDiscountPercentage": null,
                "bundleProducts": null
              }
            },
            "quantity": 3
          },
          {
            "id": "gid://shopify/CartLine/a244e897-3bd0-46a9-9e6e-a78430a66911",
            "checkBundle": {
              "value": "Yes"
            },
            "merchandise": {
              "typename": "ProductVariant",
              "id": "gid://shopify/ProductVariant/45991782973657",
              "product": {
                "id": "gid://shopify/Product/9020763373785",
                "title": "Meal Box",
                "bundleDiscountPercentage": {
                  "value": "10.0"
                },
                "bundleProducts": {
                  "value": "[\"gid://shopify/Product/8885538390233\",\"gid://shopify/Product/8885528690905\"]"
                }
              }
            },
            "quantity": 3
          },
          {
            "id": "gid://shopify/CartLine/130b6f2e-7675-4a27-96dc-a882e5c16bcd",
            "checkBundle": {
              "value": "Yes"
            },
            "merchandise": {
              "typename": "ProductVariant",
              "id": "gid://shopify/ProductVariant/46008321179865",
              "product": {
                "id": "gid://shopify/Product/8885528690905",
                "title": "5 Spice Ribs",
                "bundleDiscountPercentage": null,
                "bundleProducts": null
              }
            },
            "quantity": 1
          }
        ]
      }
    },
    "inputBytes": 1601,
    "output": {
      "operations": [
        {
          "merge": {
            "parentVariantId": "gid://shopify/ProductVariant/45991782973657",
            "price": {
              "percentageDecrease": {
                "value": 10
              }
            },
            "title": "Meal Box",
            "cartLines": [
              {
                "cartLineId": "gid://shopify/CartLine/94921826-2d97-48d4-b7d8-52830caf4468",
                "quantity": 2
              },
              {
                "cartLineId": "gid://shopify/CartLine/9955cb56-6d11-4b38-abde-59509030a1cb",
                "quantity": 2
              },
              {
                "cartLineId": "gid://shopify/CartLine/a244e897-3bd0-46a9-9e6e-a78430a66911",
                "quantity": 2
              }
            ],
            "attributes": [
              {
                "key": "_bundle_position",
                "value": "1"
              }
            ]
          }
        },
        {
          "merge": {
            "parentVariantId": "gid://shopify/ProductVariant/45991782973657",
            "price": {
              "percentageDecrease": {
                "value": 10
              }
            },
            "title": "Meal Box",
            "cartLines": [
              {
                "cartLineId": "gid://shopify/CartLine/94921826-2d97-48d4-b7d8-52830caf4468",
                "quantity": 1
              },
              {
                "cartLineId": "gid://shopify/CartLine/130b6f2e-7675-4a27-96dc-a882e5c16bcd",
                "quantity": 1
              },
              {
                "cartLineId": "gid://shopify/CartLine/a244e897-3bd0-46a9-9e6e-a78430a66911",
                "quantity": 1
              }
            ],
            "attributes": [
              {
                "key": "_bundle_position",
                "value": "2"
              }
            ]
          }
        }
      ]
    },
    "outputBytes": 970,
    "logs": [],
    "functionId": "12fffe44-2ded-4fde-a5a5-fd4478fc5174",
    "fuelConsumed": 1142445
  },
  "logType": "function_run",
  "status": "success",
  "source": "bundles-test",
  "sourceNamespace": "extensions",
  "logTimestamp": "2024-10-14T05:51:58.021294Z",
  "localTime": "2024-10-14 11:21:58",
  "storeName": "cookunity-dev.myshopify.com"
}

And it produces the following cart:

{
  "token": "Z2NwLXVzLWNlbnRyYWwxOjAxSjZFUEdHRjU0UENCNEpSMVhQQTIwNE44?key=3e47701c6a3621ff48e82789ba994457",
  "note": "",
  "attributes": {},
  "original_total_price": 23400,
  "total_price": 23400,
  "total_discount": 0,
  "total_weight": 0.0,
  "item_count": 2,
  "items": [
    {
      "id": 45991782973657,
      "properties": {
        "_bundle_position": "1"
      },
      "quantity": 1,
      "variant_id": 45991782973657,
      "key": "45991782973657:e71b8b3fd2a0cd140ca46b4e0e0720eb",
      "title": "Meal Box",
      "price": 23400,
      "original_price": 23400,
      "presentment_price": 234.0,
      "discounted_price": 23400,
      "line_price": 23400,
      "original_line_price": 23400,
      "total_discount": 0,
      "discounts": [],
      "sku": "",
      "grams": 0,
      "vendor": "cookunity-dev",
      "taxable": true,
      "product_id": 9020763373785,
      "product_has_only_default_variant": true,
      "gift_card": false,
      "final_price": 23400,
      "final_line_price": 23400,
      "url": "\/products\/meal-box?variant=45991782973657",
      "featured_image": {
        "aspect_ratio": null,
        "alt": null,
        "height": null,
        "url": null,
        "width": null
      },
      "image": null,
      "handle": "meal-box",
      "requires_shipping": true,
      "product_type": "",
      "product_title": "Meal Box",
      "product_description": "",
      "variant_title": null,
      "variant_options": [
        "Default Title"
      ],
      "options_with_values": [
        {
          "name": "Title",
          "value": "Default Title"
        }
      ],
      "line_level_discount_allocations": [],
      "line_level_total_discount": 0,
      "quantity_rule": {
        "min": 1,
        "max": null,
        "increment": 1
      },
      "has_components": true
    },
    {
      "id": 45991782973657,
      "properties": {
        "_bundle_position": "2"
      },
      "quantity": 1,
      "variant_id": 45991782973657,
      "key": "45991782973657:7c0249b50440400396fdc96855bf395a",
      "title": "Meal Box",
      "price": 0,
      "original_price": 0,
      "presentment_price": 0.0,
      "discounted_price": 0,
      "line_price": 0,
      "original_line_price": 0,
      "total_discount": 0,
      "discounts": [],
      "sku": "",
      "grams": 0,
      "vendor": "cookunity-dev",
      "taxable": true,
      "product_id": 9020763373785,
      "product_has_only_default_variant": true,
      "gift_card": false,
      "final_price": 0,
      "final_line_price": 0,
      "url": "\/products\/meal-box?variant=45991782973657",
      "featured_image": {
        "aspect_ratio": null,
        "alt": null,
        "height": null,
        "url": null,
        "width": null
      },
      "image": null,
      "handle": "meal-box",
      "requires_shipping": true,
      "product_type": "",
      "product_title": "Meal Box",
      "product_description": "",
      "variant_title": null,
      "variant_options": [
        "Default Title"
      ],
      "options_with_values": [
        {
          "name": "Title",
          "value": "Default Title"
        }
      ],
      "line_level_discount_allocations": [],
      "line_level_total_discount": 0,
      "quantity_rule": {
        "min": 1,
        "max": null,
        "increment": 1
      },
      "has_components": true
    }
  ],
  "requires_shipping": true,
  "currency": "INR",
  "items_subtotal_price": 23400,
  "cart_level_discount_applications": []
}