If you use PixelYourSite to install your Facebook Pixel and to send Conversion API events, these are the things you need to know:
1. If you plan to add new events, do it ONLY from the plugin's Events page.
2. Don't use Events Manager Events Setup Tool.
3. Don't enable "Track Events Automatically Without Code".
Only events configure using our plugin will be sent server to server and will have the required deduplication parameters.