[AddToCart] no work on IOS

Facebook Conversion API
1

When I test the Facebook API with my iphone 7, the [AddToCart] event sometimes triggers and sometimes not.

But the other events [View Content,Initiate checkout,Purchase] are all correct.

And all events are working correctly on Android phones and computers. Only in IOS the [AddToCart] event does not work properly.
! https://s3.bmp.ovh/imgs/2021/08/655dfa741745960e.png

I tested with three separate iphones and all had the same phenomenon

facebook_add_to_cart
facebook_add_to_cart1920×969 63.7 KB

I use woocommerce+Google Tag Manager For Wordpress

2

Do you have the same issue with the AddToCart browser events? If you do, then I would check how web events are set up. Because in this case, the issue might be in the web AddToCart events or dataLayer.

You can also compare the number of AddToCart events in GA4 and FB. If GA4 reports more AddToCart events than FB, most likely FB server tag for the AddToCart event is not triggering in some cases because of an error.