WordPress filtering utm_ GET variables from url unless logged in as admin, not sure w

So I am having an issue where I can’t pull variables such as mysite.com/?utm_campaign=testing unless I am logged in as admin or editor.

When logged out and just a regular users I can’t grab any variables which start in utm_ such as utm_campaign. However utmcampaign works, and any other variable I try. Just not utm_ ones.

I disabled all my plugins but still have the same issue. Not sure where the filtering is coming from and not sure why it only filters when not logged in as admin.

I tried accessing the variable using three different methods:

  1. Injecting PHP code using the “Code Insert Manager” plugin
<?php echo $_GET['utm_testing']; ?> 

  1. Using the built-in function of formidablepro to grab the GET variables.

  2. Using the same code as #1 but inside my footer.php file of my template.

All have same results.