Why resources loading passed into BeforeEnterEvent ?

I added the code into my MainView

public void configurePage(InitialPageSettings settings) {
    settings.addLink("shortcut icon", "icons/favicon.ico");

and now I catch navigation to icon/favicon.ico in my BeforeEnterEvent declared in

public class ConfigureUIServiceInitListener implements VaadinServiceInitListener {

public void serviceInit(ServiceInitEvent event) {
    event.getSource().addUIInitListener(uiEvent -> {
        final UI ui = uiEvent.getUI();

Also I saw navigating to sw.js here too.

I expected to see here requests of routes only, not any resources.
What do I wrong?

I found the post: https://vaadin.com/forum/thread/17689559/bug-in-flow-when-there-s-no-pwa-in-the-application
It cleared navigating to sw.js (I used PWA and then disable it).