I was having issues figuring out why we were reaching a hard limit on upload size even after doing all of the normal fixes though wp-config, .htaccess and apache. We found out the issue was with the all-in-one-security plugin. The all-in-one plugin overrides the apache limit size on instantiation. line 332-333 of  wp-security-utility-htaccess.php

//limit file uploads to 10mb 
$rules .= 'LimitRequestBody 10240000' . PHP_EOL;