Why is the wrong product variant being added to my cart?

Technical Q&A

Topic summary

Issue: A customer reportedly had the wrong product variant (option selection) added to cart. A console screenshot was shared suggesting a possible variant data problem, but details of the error aren’t provided.

Context: Shopify store babyscoffee.com using the Dawn theme v9.0. An update to v11.0 is available, but the updater warns that custom code changes conflict and won’t carry over automatically.

Troubleshooting so far: Another participant tested the site and found it working correctly, asking for a specific product URL to reproduce the issue. The product link provided was for “Baby’s Breakfast Roast®,” and the reporter noted they cannot reproduce the problem themselves; it appears limited to one customer.

Current status: The problem is intermittent and not currently reproducible by others or the site owner. No fix or concrete cause identified yet.

Next steps/outstanding needs: Further details are required (e.g., exact steps, device/browser of the affected customer) to isolate the issue. Discussion remains open pending reproducible evidence.

Summarized with AI on January 17. AI used: gpt-5.
1

I have a problem where a customer has added a product to cart, but the wrong variant ends up in the cart.

Attached is a screenshot of the console that seems to show a problem with variant data, but I’m lost how to fix this.

Website is : babyscoffee (dot) com

Theme: Dawn version 9.0 (noticed there is an update to 11.0 available, but there is a dialogue box that says: "Your code changes won’t be included because one or more changes conflict with the update. After the updated theme is added to your theme library, you will be able to copy your code over or re-configure some apps. ")

Any help greatly appreciated!!

console1.PNG
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2

@coffeed

I have checked your site and it seems to be working properly. Can you please share the product URL where you are facing issue.

Thanks

3

This is the product: https://babyscoffee.com/products/babys-breakfast-roast%C2%AE

I cannot figure out why this one customer is having a problem. It appears to be working for me.