Four digit hash is showing up before each php include when using AT&T 4G network

Question

As far as we can tell, only AT&T network requests are displaying this issue.

Before any php include that actually prints to the DOM, we are getting a variety of 4-digit (and sometimes 3-digit) hash codes such as 3288 and 3c14 displaying in the DOM (and on the web page).

Answer 1

In the end, it turns out AT&T needs your headers when you're running an old LAMP stack.

Add the following to the .htaccess file:

Header set Cache-Control "no-transform"

Or you can set it specifically in PHP;

header("Cache-Control: no-transform");

We got to the solution through the help of iOS Web page errors over Cellular Data but not over Wifi? Recent change to AT&T Cellular network? and https://serverfault.com/questions/629981/android-browsers-adding-random-numbers-to-php-files