Why does the referring_site parameter return NULL in some API responses?

[coolmac]

Hello everyone,

We've been using the Shopify API for some time now.

Through your API, we retrieve a list of our orders using "/admin/api/2023-07/orders.json?status=any".

API Documentation: Link to API Documentation

As we operate various landing pages and promote products through the Buy Button, we've configured different alias subdomains under "Settings > Domains" in Shopify. This enables us to send appropriately branded emails to our customers.

Lately, we've noticed that in approximately 10% of orders, the "referring_site" parameter returns a value of "NULL."

Unfortunately, we can't explain this and are seeking assistance to determine if we are doing something wrong or if there is a reason for "NULL" being returned via the API in 10% of cases-

API Documentation: Link to API Documentation

Best regards,