Issue with CART API

[edisonid]

Good day I have one questoion.
Lets imagine this scenarion: We have product X which has in stock only 2 items.
I have added one with property name:"Bob" and other one with property name:"Lia"
So we have 2 same product in cart but since line item properties are different we are getting 2 different lines which is correct. What will happen if I add one more to the cart ? Sure error since we have only 2 in stock, but something strange is that Shopify will merge all our 2 separate line items into one and put quantity 2 without property "name".
Let me know how to overcome this thatnkss