Understanding checkout rule error messages in Shopify

If you see warning messages in your Shopify checkout rules for Simple Bundles cart transform or cart validation functions, this guide explains what they mean and why they are unlikely to cause issues for customers placing orders.

What the warnings look like

You might see messages like these in your checkout rules:

These warnings appear in the checkout rules section of your Shopify admin and mention that some customers abandoned checkout or couldn't submit orders.

Why these warnings appear

These warnings are caused by bot activity, not real customer issues. Here's what happens:

• Competitors and data scraping companies use bots to visit your store
• These bots add hundreds or thousands of items to carts to collect inventory data
• The bots then leave without buying anything
• This high-volume activity triggers the warning messages

Real customers adding normal quantities (1-20 items) to their cart won't experience any problems.

Your customers can still check out

The most important thing to know is that your customers can complete their purchases even when these warnings appear.

By default, the "Allow all customers to complete checkout" option is enabled. This means:

• Customers can always complete their purchase
• Payment processing works normally
• In the worst case, bundles might not break down into individual items
• Customers can still buy the bundle as a complete product

What the logs show

When we review the actual error logs from stores with these warnings, we consistently find:

• Failed attempts involve 100 products added to a single cart with tens of thousands of quantities each
• These attempts come from automated bots, not real shoppers, as they always involved the maximum items allowed in cart, e.g. 100
• No real customer purchases are affected
• Bundle orders continue to process correctly for customers checking out.

Error: InstructionCountLimitExceededError

Shop ID: [REDACTED]
Shop Name: [REDACTED]
Domain: [REDACTED].myshopify.com
Date: June 10, 2025 at 10:23:08 PM

Resource Limits:
Input Size: 30.48 kB (Limit: 128 kB) ✓
Instruction Count: > 11M (Limit: 11M) ✗
Output Size: N/A (Limit: 20 kB)

Input (STDIN) (Cart Contents):
{
  "cart": {
    "lines": [
      { "id": "gid://shopify/CartLine/0", "quantity": 12438, ... },
      { "id": "gid://shopify/CartLine/1", "quantity": 12437, ... },
      { "id": "gid://shopify/CartLine/2", "quantity": 12436, ... },
      { "id": "gid://shopify/CartLine/3", "quantity": 12435, ... },
      { "id": "gid://shopify/CartLine/4", "quantity": 12434, ... },
      ...
      [95 more cart line items with similar high quantities]
    ]
  }
}

Total Cart Lines: 100 items

What this means for your store

These warning messages don't indicate problems with your store:

• Your customers are checking out successfully
• Bundle orders are processing correctly
• You're not losing sales due to checkout errors
• The warnings are just Shopify's way of reporting bot activity

Recommended fix: turn on the add-to-cart limit

Shopify has a built-in feature that allows you to set a maximum quantity per item that can be added to a customer’s cart. The recommended default is 50 units per product.

This limit serves several purposes:

• Protects your inventory data from being revealed through error messages.
• Prevents abuse or scraping of stock levels by bots.
• Keeps checkout fast and stable, even for high-traffic stores.

To avoid these checkout rule errors with Simple Bundles, we recommend enabling Shopify’s add-to-cart limit and setting it to the recommended value for your store.

Here’s how to do it:

1. In your Shopify admin, go to Settings > Checkout.
2. Scroll to Checkout rules and click Add-to-cart limit.
3. Toggle the setting On
4. Click Done to save your changes.

This setting helps ensure that your bundles work seamlessly and your inventory stays protected.

When to contact support

You should reach out to our support team if:

• Bundle orders stop breaking down into individual items
• You want us to review your specific error logs
• You need help interpreting any unusual patterns

How we're addressing this

We're working with Shopify to improve how these warning messages are displayed. The current messages can be misleading because they suggest customer checkout problems when the real issue is bot activity.

Until Shopify updates their messaging, you can be confident that these warnings don't affect your real customers or sales. Please reach out to our support team for any questions related to these error messages.