Using both Google Tag Manager for WooCommerce and Facebook for WooCommerce plugins is good idea to ensure:
- great events coverage and Consent Mode compatibility (thanks to GTM integration)
- ability to synchronise Facebook Products Catalog and use other native features (thanks to direct Facebook integration)
The problem is that when Facebook is integrated using both plugins it will cause duplicates in tracking. Facebook/Meta Pixel will be loaded twice and all events will be tracked twice.
1. Ensure Facebook Pixel GTM preset is installed
Follow this dedicated guide to ensure GTM is correctly integrated with your Facebook / Meta Pixel
How to integrate Facebook / Meta Pixel with WooCommerce?
2. Disable Facebook Pixel in Facebook for WooCommerce
In order to resolve the problem use built-in PHP hook of the Facebook for WooCommerce plugin that allows to prevent it from loading Facebook Pixel and only rely on GTM integration.
Facebook for WooCommerce hook documentation
Open functions.php of your WordPress theme and paste this PHP code:
add_filter( 'facebook_for_woocommerce_integration_pixel_enabled', '__return_false' );
Save the file and this will ensure Facebook Pixel is not loaded twice corrupting reporting.