Google Optimize Experiment targeting wrong URL

I've setup an experiment on a specific URL in which I send no traffic (same domain name that I use for other landing pages but with different parameter in the URL)

I've started the experiment few days ago without sending any traffic And now I see that the experiment got triggered around 5000 times. I double checked on my analytics reports and I see no access to the main page that is supposed to trigger the test. To explain with example:

This is what I have running:

http://domain1/landingpages?id=1

http://domain1/landingpages?id=2

this is the test that I created:

http://domain1/landingpages?id=3

with a 50% redirect on:

http://domain1/landingpages?id=4

The Experiment should only be triggered on id=3 page, but it did got triggered with id=1 and id=2 pages. Any idea how I can make the trigger only happen when "id=3" is in the url ? Currently my configuration is as follow:

"WHEN Url Matches "http://domain1/landingpages?id=3" "

The URL targeting documentation explains your situation. (Emphasize by me.)

Use matches when there are query string parameters in URLs that you don’t want to include in the matching. Matches can be more flexible than equals because it adheres to the following rules:

• Ignores query string parameters and fragments.
• Case insensitive.
• Normalized to remove a www. prefix.
• Normalized to a remove a trailing slash.
• HTTP and HTTPS are optional (HTTP will match HTTPS).

Verifying this in Optimize:

So you should either simply select Equals operator and use http://domain1/landingpages?id=3 as a value.

If other parameters might occur, then you could build a regex for this, to containt id=3 among various parameters. E.g.:

http:\/\/domain1\/landingpages\?(.*&)?id=3(&|$)

Optionally, you can use Query parameter targating, and build a rule for the base URL, and for the id parameter separately.