a Twig_Error_Loader only appears on apache logs

I am getting a blank page from an extension without any errors, even though, all two debug options are enabled in config.php.

I can only see the error from the servers apache error logs.
This being a Twig_Error_Loader, it should be handled by phpbb.

The error and more about the subject at this url:
https://www.phpbb.com/community/viewtopic.php?f=466&t=2306361