Same issue, was doing an empty() check on $page_urlname in Admin:PageManager and not taking both main pages into account
# Thanks to http://phaedo.cx/archives/2007/07/25/tools-for-optimizing-your-website-etag-and-expire-headers-in-django-apache-and-lighttpd/ for this.
FileETag MTime Size
# http://www.askapache.com/htaccess/apache-speed-expires.html
<IfModule mod_headers.c>
<FilesMatch "\.(jpg|jpeg|png|gif|js|css)$">
Header set Expires "Wed, 1 Jan 2020 20:00:00 GMT"
</FilesMatch>
</IfModule>
# http://www.askapache.com/htaccess/apache-speed-compression.html
<IfModule mod_deflate.c>
<FilesMatch "\.(js|css)$">
SetOutputFilter DEFLATE
</FilesMatch>
</IfModule>