It's a bit curious. My Google Analytics installation seems to be working fine for the e-commerce shop I am working on. Visits and purchases are being recorded properly. However, I have noticed that a few purchases are not being recorded by Google Analytics E-commerce. And what those purchases have in common is that the traffic came from Facebook. The Facebook Pixel is installed properly, and it is sending transaction data for 100% of purchases, regardless of traffic source, as per data in Facebook Analytics / Facebook Ads Manager.
Sooo ... I am suspecting that Facebook in-app browser is preventing Google Analytics from registering purchases while Facebook Pixel is registering the purchase as normal. This seems to only be the case with traffic being generated from Facebook Ads Links and subsequent purchases with Facebook In-app Browser.
Has anyone experienced the same thing? Could there be another explanation that Google Analytics E-commerce malfunctioning for a small portion of purchases? Could Facebook and Google tracking services somehow be interfering with each other for this scenario?
It is also weird because I can see traffic from Facebook Ads, so this problem is only for purchase data.
I have't published any code here since I don't think that the code is the problem.