Hello,
Despite my initial assumption, the server:stop does not actually stop the web server. It displays all-is-good message, but I can still access the app under 127.0.0.1:8000. What is more, there is no way for my to shut down the process aside from running kill PROCESS_PID.

This has changed since upgrading to 3.3.5 from 3.2.11 (PHP 7.1.7).