Why doesn't the redirect to the google optimize experiment work?

Question

Marketing

Good day!
The problem is this:
There is a site on it, through google optimize, an a / b experiment (or aab) with three pages is configured. Original (page), o-page and n-page. The experiment only works when visiting the page page.
The site also implements the display of a consent feed using cookies (by clicking on the consent button, a site cookie with utm tags and a flag cookie are added, according to which the feed will no longer be shown in the future). The button also has a Google view and click tracking event.
So, when I go to the page page, the experiment is triggered, I am transferred to one of the new pages (let's say n-page), the Google cookie of the experiment with the number 2 is recorded. Then I go to any other page of the site, then I click on the page page and, instead of in order to get n-page, I get the original page. That is, the redirect did not work, although there is an experiment cookie and the number is still 2.
The most interesting thing is that if you accept and write down the cookie flag, everything starts working. We thought that the problem was displaying the cookie accepting feed (a Google event conflict on the button), but no, with disabled events, the redirect still does not work.

I noticed that when the redirect is running, a temporary _goexp_rc cookie appears, but I could not find anything about it.

Maybe someone faced similar?

Answer 1

One solution is to pull out the utm_expid value and assign it to a new utm tag, and then collect all the tags in a bunch.
But I would still like to understand why.