How do I tell if the redirect on my site is due to a Google Optimize test?

On my site right now, I have an alert that appears before the user leaves the site asking them if they're sure they want to leave.

This is interfering with a Google Optimize test I'm running because the test is redirecting traffic from my main page to two variant pages and causing the alert to appear as soon as the person hits the page.

I was wondering if anyone knows if there's an event fired with these Google redirect tests or if there's a way to tell when a redirect is happening or who it's coming from, so I can properly handle it.