We're using Google Tag Manager to load GA into the site (on gtm.load). We load Google Optimize tag on top of that, using Google's recommendations (https://support.google.com/optimize/answer/6314801?hl=en). This requires the loading of GA to be a trigger for the Google Optimize tag. We also use the anti-flicker snippet (https://support.google.com/optimize/answer/7100284?hl=en). With this setup, when the page is done loading, there are two instances of analytics.js showing up in the DOM. Now different web optimization sites are telling me the script is loaded and parsed twice, which is of course unwanted behaviour.. But I'm not sure if that's actually the case, because I'm not seeing anything that points to that when looking at the chaining, for instance.
Is this normal behaviour?