Elastic Beanstalk Docker AL2: Disk full after /var/log/nginx filling up, with nginx disabled

Today one of my prod environments stopped working. EB Health stated "100 % of root file system is in use. The following services are not running: eb-docker-log".

After logging into the EC2 instance via SSH, I was able to find the cause: Inside the Docker container, /var/log/nginx was filled with (rotated) log files (naming pattern: eb-xxxxx-stdouterr.log), but the content is the console output of my .NET application.

I have the following setting in my options.config:

  aws:elasticbeanstalk:environment:proxy:
    ProxyServer: none # no additional nginx

And there is actually no nginx process running, and my application is exposed directly to the load balancer as expected.

I can confirm this behavior for both environments of one of my application, for different platform versions (the prod problem occurred with 3.5.6; I reverted the test environment back to 3.5.3 and it has the same behavior).

I cannot confirm this behavior for another application, which is still running on 3.5.3. Both are .NET applications and have very similar architecture, logging configuration, and EB settings (both with ProxyServer: none and aws:elasticbeanstalk:cloudwatch:logs StreamLogs: true).

Any idea why my application console output is written into /var/log/nginx for one of my applications and filling up the disk?

Thank you!