Fb App Kills my site analytics

I have a very unusual bug with the Fb app.

Using the Facebook browser app on my website kills my sites tracking system.

Normally my site will fire a request to my tracking app with the details of the element that was clicked. On all browsers this works fine.

But on Facebook on 50% iOS devices the click requests populate with null data. Most send to tracking app and some don’t even get sent. Also this is with latest Fb app and latest iOS. My friends tested with me. Their phones bugged while mine worked (all iPhone)

So in summary : Using Fb app on iOS bugs out my fetch requests to my tracking server and I don’t know how to debug it.

I’ve tried: I’ve used alerts before and after a click event. Before the click is sent the data always exists so the issue comes during fetch event.

Any ideas what the Fb browser does that messed up my fetch requests??