Facebook Pixel Purchase Event Not Firing in Latest Versions

[dous11]

🔎 Isolate the bug
I have confirmed this occurs in the most recent version of WordPress, WooCommerce, and Facebook for WooCommerce.
I have confirmed this occurs when only WooCommerce and Facebook for WooCommerce are active and when using a default WordPress or WooCommerce theme.

✍️ Describe the bug

After updating to the latest version of Facebook for WooCommerce, the Facebook Pixel Purchase event is no longer firing on the “Order Received” (thank you) page.
This happens even with the default WordPress “Twenty Twenty” theme, so the issue is not theme-related.

In previous versions (e.g. v3.0.16), the Purchase event worked perfectly.

This breaks conversion tracking for Meta Ads.

🚶‍♀️ Steps to reproduce

Install latest versions of WordPress, WooCommerce, and Facebook for WooCommerce.

Use the default Twenty Twenty theme (no customizations).

Complete a test purchase (checkout and order confirmation).

Check Meta Events Manager or use the Meta Pixel Helper.

The Purchase event is not triggered.

✔️ Expected behavior

The Purchase event should fire and be sent to Meta/Facebook after a successful WooCommerce order.
🗃 Logs

WooCommerce System Report

Facebook for WooCommerce: par Facebook – 3.5.9
WooCommerce: par Automattic – 10.2.2
Theme: Twenty Twenty
Other plugins: None
Environment: Clean WordPress install, no cache, no optimization.

🧩 Additional context

I also tested with a custom theme that uses AJAX for “Add to Cart” (slide-in cart sidebar).
In that case, AddToCart and Purchase events fail as well — but even with the default Twenty theme (no AJAX), the issue persists.
So this confirms that the bug comes from the plugin update itself, not from the theme.