title: Google Analytics with Google Tag Manager not reporting properly on subdomains
body: <p>I have a site with 3 subdomains with the same Google Tag Manager and Google Analytics tracking ID. I created 3 views on the property, I applied the proper inclusion filters so I can focus each view on its counterpart subdomain.</p>
  
  <p>GTM is firing GA on the three subdomains and the GA debugger is showing that it is tracking (I tried recording and it worked, I tried GA plugin and there are no errors).</p>
  
  <p>The problem: One of the subdomains is reporting everything (all subdomains)! Even with the proper inclusion filter in place. The 2 other subdomains are reporting nothing.</p>
  
  <p>Note that my inclusion filter is equal sub1.example.com (and the same view is reporting on sub2.example.com and sub3.example.com)</p>
  
  <p>I spent 6 hours so far, reading documentation and trying different options to no avail.</p>
  
  <p><strong>Why would be a filtered view for one subdomain show stats for the other subdomains? Why would the other subdomains show nothing? Would this be related somehow to GTM?</strong></p>
  
  <ul>
  <li>GTM id is the same across the domains and not duplicated and matches the account number</li>
  <li>GA snippet is not included on the pages and the id is double checked</li>
  <li>The three subdomain settings are exactly the same with only the inclusion filter being different</li>
  </ul>