Passing system variable to Apache stopped working

Question

We rebooted one of our servers over the weekend and now Apache won't pass through the host name - not sure whats wrong. Here's my config:

LoadModule                          headers_module modules/mod_headers.so
LoadModule                          env_module modules/mod_env.so

<IfModule headers_module>
    <IfModule env_module>
        PassEnv                     HOSTNAME
        Header                      always set X-Host-Name "%{HOSTNAME}e"
    </IfModule>
</IfModule>

I am running as a user other than root. I am able to execute sudo -u websrv "printenv" and the value for HOSTNAME appears appropriately.

Not sure whats going on