Why does the wrong product size keep getting added to the cart?

[TextualTees]

THE PROBLEM

So two or so years ago I switched from Shopify Plus back to a regular Shopify plan when our business took a nose dive.  Shortly after we started to notice random customers reporting that they were getting the wrong product sizes.  If someone wanted a XL t-shirt they ended up with a small which is the first option for sizing.  Customer selects the product option they want, clicks the add to cart button and then a small ends up in the cart.  After a few more people reported this we started to log all of the cases and it looks to be completely random and not related to a size, device, or browser however a small which is the first product option always seems to be what this bug reverts to.   A customer can have a few shirts in their cart and it may only happen to one of the shirts in the cart.  One person said they noticed the bug, removed the item from their cart and tried to add it 4 more times and each time it went to small.  It's only the 'Size' product option.

WHAT I'VE TRIED

• I've contacted Shopify support 3 times now over the past 2 years and each time they say they are unable to figure out what the problem is.  Each time after reviewing they send the ticket to a senior support person and they still didn't find anything.  
• I've deleting apps thinking it was related to one of those but still we have not been able to fix the problem. 
• I've switch Shopify themes twice since this started happening.  All themes from different companies.

CONCLUSION

At this point I am lost and have no idea what else to do.  This bug is costing me serious money and customers.  I find it hard to believe that I am the only person who is experiencing this problem.  If anyone else has or is seeing this can you please let me know?  At this point I've already started building another site on another platform but moving over 900+ products is going to be a massive pain.  Any help anyone can give would be greatly appreciated.  

[AshleighLou]

the same thing is happening to me- did you find an answer?

[Joseph_Levatino]

We have also experienced customers complaining that the item added to cart does not match their selection.

[stylishoutback]

My website is:  www.stylishoutbackclothing.com.au

On my clothing website each item has a number of size options. 

When customers are choosing their size, the website defaults to the smallest size even though they click on their desired size.

It does this many times per day on a large proportion of my orders. Please advise what I can do to stop this happening.

I know a number of other Shopify stores have this same problem. PLEASE FIX.

Thank you,

Janice Grey

[bluestreetmedia]

I see lots of people seem to be having the issue of when a customer chooses a product size, after adding it to the cart, the size is defaulted back to the first size in the list. For example...if you choose a size XL, add it to your cart, go to cart, you will see that it now is back to Small, which is the first size variant in the list?

I have also asked Shopify, and the developer of the theme BOOST...anyone have any luck figuring this out?

[Zoe_Store]

How do you solve it ? we are having the same issue using ICON theme 2.0 update. 

[fullboost]

Having the exact same problem with Venture theme.

Only happens on mobiles, browsers seem random. I can replicate it using the Samsung browser.

[Lisajlb]

July 2023 and on v2 and we are too seeing the same issue. Has anyone found any solution? The feedback I am getting seems to be on an Apple Iphone