I need to send a custom parameter called 'purchase_type' from my Client's Shopify website which contains information about if the order is a one-time or subscription.

I'm sending that data through a daltaLayer variable to GTM where I've set up a tag that triggers on the purchase event and is supposed to send the data to Meta Pixel.

Here's my code to capture the 'purchase_type' and send it to the datalayer:

Inside GTM, when a purchase event happens, I receive the correct data in this format: { event: "purchase", gtm: {uniqueEventId: 15, start: 1727286086267}, purchase_type: "one-time", total_value: "0.00", currency: "USD", developer_id: {dYWRkMT: true}, ignore_referrer: "true", eventModel: { transaction_id: 5024419315789, value: "0.00", currency: "USD", tax: "0.00", shipping: "6.00", items: [ { id: "shopify_US_6801620729933_39871623266381", name: "Idido - 12 oz", brand: "Counter Culture Coffee - Retail", category: "Coffee", coupon: "HTTEST_100_OFF", price: "22.00", quantity: 1, variant: "12 oz" } ], ignore_referrer: "true" } }

I've created a tag that fires on the Purchase event and it's supposed to send three properties to the Meta Purchase event - currency, value and purchase_type. However, the purchase_type data just doesn't appear inside the Purchase event.

Please help me figure out where the gaps are and how can I fix this