GTM Ecommerce Tracking Issue - google-tag-manager

Question

I am expecting someone to help me on the below. Below is the scenario
We are planning to track revenue, products sold etc and we have setup standard ecommerce tracking using GTM on my test domain. If the ecommerce tracking works fine on the test domain then, we have planned to move it to live.
Trigger I have setup
enter image description here
Tag I have setup
enter image description here
Data layer code placed on Confirmation page above the GTM container immediately after opening the tag
<script>
window.dataLayer = window.dataLayer || []
dataLayer.push({
'transactionId': 'XYZ',
'transactionTotal': 123,
'currencyCode': 'SAR',
'transactionProducts': [{
'sku': 'abcd',
'name': 'iphone',
'category': 'Mobile',
'price': 999,
'quantity': 1
}]
});
</script>
Here the problems are
1) Whenever someone lands on confirmation page in real time goal conversion visitors are showing as
two instead of 1 for that confirmation page.
2) I did continuously 4 bookings but only one booking is showing in goal conversions option and also
ecommerce tracking is also showing for that one booking only. But for all the 4 bookings GTM tag
triggered and also in real time conversions it showed for that 4 bookings.
3) After 15 mins again I made a booking then, that booking is tracking in analytics and showing
under conversions option.
I just want to know why does this happen. Why analytics is not tracking goal conversions if I do
bookings continuously from my system. Why it is tracking after that 15 mins of time.

Answer 1

2) Goals are registered only once per session, so unless you wait 30 minutes or remove the cookie the goal will be completed only once. Also if you re-use the transaction id this will be merged into a single row in the reports (try and set minutes as secondary dimension, that should break up transactions into different rows). Better use different transaction ids for testing (maybe random strings).
3) It seems by then your session has ended (unusual, session should be 30 minutes by default, or until a change of traffic source) and so conversions are recorded again.
As to 1) no idea really - if two users show up that would mean you create two GA sessons with different client ids, but there is nothing wrong with your trigger. I don't think this can be diagnosed without looking at your page.