I have GA set up with external payment gateway. The cross-domain linker properly tracks both website and the payment gateway. Ecommerce tracks all referrals correctly (direct, organic, newsletters etc.) however social media (Facebook) doesn't show up or has really low numbers as referral e.g. 1 transaction per 2-3 months. The traffic via Facebook on the other hand is fine when I look at Acquisition. We have regular Facebook & Instagram campaigns - 3-4 posts per week, both paid and non-paid.
I tested in real time by visiting a web link on Facebook, it tracks me down in GA showing Facebook as a referral. Then browsed around the website, jumped on the booking link - all works fine - tracks me as one session, still showing Facebook as a referral. Then stopped any activity for 7-8 minutes and when I came back and clicked on another link, Facebook wasn't referral anymore, I was tracked as a direct visit.
Not sure if that's the issue or if it's an issue at all but I would really appreciate any advise.