Snipcart api cart items update not working

Hello Snipcart community and support team,

I’m having problems updating the quantity of a product in cart. I’m using Snipcart.api.cart.items.update but it never finds the item, while remove does.

Can anyone explain me what is going bad here? I don’t see a problem… Also i have tried with product ID instead of uniqueId and the result it’s the same…

Thank you for your time and effort!