Strange behavior of the cart when the product in the bundle is no longer available

[alex-cool-tech]

I discovered a strange behavior that prevents me from editing the number of several bundles in one cart (expand operation)

Let's imagine that there are 2 bundles (2 different line items, same content, i take the data for the content from the line item properties of the bundle product)

• 1 bundle x 2 (CartLine ID: abc)
  • content product variant with ID 1, quantity 1
  • content product variant with ID 2, quantity 1
• 2 bundle x 1 (CartLine ID: bcd)
  • content product variant with ID 1, quantity 1
  • content product variant with ID 2, quantity 1

When I try to add a quantity to the 1 bundle and its product content is no longer in stock (I get the expected error that we cannot add more of this bundle), then sometimes these 2 bundles are merged into one. How is it possible? Their CartLine ID is different

At the input of the function, the CartLine of the first bundle comes (with quantity 3), that is, Shopify itself converts something even before executing my function

Need your help, thank you!