Premature end of script headers

For some reason right after updating to PHP 5.6.30 I am getting this error. The websites are now giving an erro code 500.

Here's my configuration:
PHP: 5.6.30 run as FastCGI application served by Apache
memory_limit: 2048M
max_execution_time: 3600
max_input_time: 3600
post_max_size : 310M
upload_max_filesize: 300M
opcache.enable : on (default)

This configuration above is working just fine eversince, until I get this PHP update which renders my website down.

Any suggestions?