Recently I had an internal server error, running two virtual hosts of OJS on Apache 2.4 and PHP 5.6 with opcache enabled. On some pages I had internal server error with lines in logs:
mod_fcgid: get overlap result error
[core:error] [pid 11288:tid 2604] [client 192.168.1.11:16907] End of script output before headers: index.php, referer
I tried to disable opcache extension and error was gone. Is there any way to make it work with opcache?