title: Cross-domain tracking URL parameters appearing on sub-domains
body: <p>We're running Google Tag Manager on several domains and several sub-domains and using Cross Domain Tracking and Sub Domain Tracking as detailed in <a href="http://www.lunametrics.com/blog/2015/06/16/cross-domain-tracking-with-google-tag-manager/" rel="nofollow">this Lunametrics blog post</a>.</p>
  
  <p>As of a few days ago, the cross-domain tracking url parameters (?_ga=) started appearing on sub-domains when clicking from say www.example.com to secure.example.com - which to my understanding it should not be doing.</p>
  
  <p>This is causing havoc to some of our login systems. In this time no changes were published from GTM.</p>
  
  <p>I'm trying to find out from our IT team if they made any server side changes but I'm pretty clueless when it comes to back-end and am hoping some smart people here might be able to make some suggestions as to what is causing GTM to start treating sub-domains as cross-domains.</p>