When viewing a stream in Web View UI, you can click ‘detach’ (Picture-in-Picture mode), which will pop out the viewer, and then click ‘full screen’ button (or press F), and view the stream in full screen. This is all good and expected behavior.
However, when you click fullscreen button directly (without detaching first), it tries to open a new stream, puts ‘Connecting…’ overlay message on screen, and often takes 30 seconds to a minute to load into same fullscreen view. This is not an expected (or desired) behavior. This is by far the worst part about web view, and needs to be addressed.