I have been trying to get this to work for sometime and there seems to be very little information on how this works.
First, I would like to say that I tried the belo
Here's what worked for me
For the pages in the Experiment, I implemented Google Analytics the "old fashioned way" with analytics.js instead of GTM.
I tested (with Realtime analytics) this and the Experiment page and the Google Tag Pages both report data.
I did post asking if there might be conflicts from ths.