Not really a bug - more of a suggestion ...
In macOS, when playing in windowed mode, if you click to close the window, there is no verification if you actually want to quit the game.
Steps to Reproduce
Go to windowed mode - Command F to exit Full Screen Click the Close Window icon on the Window (the red circle on the top left corner of the window) Game Quits without confirmation
This issue has not been confirmed by a developer yet.