Facebook pixel num_items parameter to be used on AddToCart event

Hello,

We have an app managing Facebook pixels and we have a question regarding the recommended implementation.

We noticed the num_items property is sent inside the AddToCart event by Shopify’s 1st party Facebook pixel integration (from dashboard >> facebook sales channels >> setup), but the Facebook’s documentation says that num_items is supposed to be sent (only) in the InitiateCheckout event.

We want to understand the reason why Shopify doesn’t respect the guidelines and sends num_items in the AddToCart event, and we want to know if it’s better we also do the same for our clients.

Let me know if I can help with more details.

Thank you,
Alex