We have an issue with the item being added twice in the cart for the last few months, and we are unsure why this is happening.
Our Magento Version is 2.3.4 Commerce Cloud.
The issue is, duplicate items get added automatically to the cart page when the customer is adding items to the cart or when checking out or after checkout.
For example, the customer adds 10 items to the cart, and after checkout or during checkout, we can see 20 items in the cart, which means the same 10 items are added again to the cart as a new row in the quote.
NOTE: All the items on our website are grouped products.
We call all the customers who have this issue to ensure that they are not adding the same item twice in a cart and find they are not adding the same item in the cart, but it's automatically added.
This issue is random, and we cannot reproduce and happen once a month.
If anyone has the same issue or shows us a path to find this issue, it will be much appreciated.