Help needed: No output from php://stdout in frankenphp log

Hi,

I have a simple app with PHP 8.3/Laravel/Octane which I want to put in container. I use Laravel sample logging config 'single':

        'single' => [
            'driver' => 'single',
            'path' => 'php://stdout',
            'level' => env('LOG_LEVEL', 'debug'),
            'replace_placeholders' => true,
        ],

Starting this app (without container) with:
php artisan octane:frankenphp --log-level=debug
produces caddy access log, but no application logging is shown.
If I set path to 'php://stderr' - it works as expected. Of course it works as well if I log to a file.

Is there some configuration I am missing to emit application log on stdout to caddy/frankephp logger?

Reproduce the issue with the Laravel logging configuration using php artisan octane:frankenphp --log-level=debug, comparing php://stdout and php://stderr. Trace how application output is handled by FrankenPHP and its Caddy logger; done means identifying whether this is expected behavior or a configuration defect and documenting or correcting the result.