Today I have faced a weird issue where modpagespeed off was not working in htaccess file. It was only working if we disabled it in vhost file in the cPanel. Easyapache 4 by default loads all php version with cgi handlers. modpagespeed off was not working due to handler problem. Generally to disable pagepseed module of particular domain you need to mention below code in htaccess file
Above code was not working when handler was set to cgi, To fix this I have changed the domains handler to suphp and that code started working.