Google analytics tracking. I can't find where is coming from - google-analytics

Question

I am auditing your Google Analytics account, and because of the non-standard implementation, I can't figure out how GA (universal analytics) is pushed into the site. Google Tag Assistant is detecting the Google Tag Manager container, but this is not where tracking is initiated (container is empty).
This is all that I see :
<script async="" src="https://www.googletagmanager.com/gtm.js?id=GTM-NVMXXXX&gtm_auth=&gtm_preview=&gtm_cookies_win=x"></script>
<script async="" src="https://www.google-analytics.com/analytics.js"></script>
<script>
(function(w,d,s,l,i){w[l]=w[l]||[];
w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js', });
var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';
j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl+'&gtm_auth=&gtm_preview=&gtm_cookies_win=x';
f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-NVMXL73');</script>
Update:
There is no UA-related item in the devtools>network section. I can see only analytics.js
Tag Assistant occasionally only registers GTM. On refresh, it shows the correctly executed tag sometimes, and the UA tag with an error other times.
Error :
At the same time, I'm looking at a real-time UA report, and the site is definitely being tracked.
I hope someone can shed some light on this. We are looking to move tracking to Google Tag Manager but are unsure where the current tracking is coming from.

Answer 1

Maybe the problem is that you are watching a different google tag manager account so you can not see the container full.
Ensure you are administrator and that you are using an administrator acount.
If you are not the administrator, request via google tag manager or via google analytics become one. Then you will be able to see the container full.

Answer 2

The GA might only comes from GTM or hard code on website.
Here is a way :
Open the devtool
Search for the UA property id in Network
Click one of the request
See the Initiator, there should have information about it is coming from tag manager or hard code to website.
Or you can share the screenshot from your side and let us check.
Update
From the screenshot you provided.
It's installed through hard-code in the loadGA.js
You might need to see if you have the permission to check the source code or you need to ask the related developer to do it for you and remove them.