Custom loading animation not instantly shown on page reload

For my webapp I implemented a custom loading animation. It is working just fine but when a user opens the site for the first time or after a page reload the stock vaadin animation is shown for a brief moment which makes it look a bit weired because the stock animation is mergin into my custom animation (which is centered and without steps)

Vaadin 15 code to implement custom loading animation

public class AppShell implements AppShellConfigurator, VaadinServiceInitListener {

@CssImport("./styles/loadingIndicator.css")
public class AppShell implements AppShellConfigurator, VaadinServiceInitListener {

	private static Logger LOG = LoggerFactory.getLogger(AppShell.class);

	@Override
	public void serviceInit(ServiceInitEvent serviceInitEvent) {
		serviceInitEvent.getSource().addUIInitListener(uiInitEvent -> {
			uiInitEvent.getUI().getLoadingIndicatorConfiguration().setApplyDefaultTheme(false);

			final UI ui = uiInitEvent.getUI();
			ui.addBeforeEnterListener(this::beforeEnter);
		});
	}

Stock animation mergin into custom animation
![Stock animation mergin into custom animation]
(https://i.imgur.com/vBmvwUV.gif)

Is there any way to disable the stock animation instantly/ at all?

For everyone else wondering there is an open ticket with a similar problem:
https://github.com/vaadin/flow/issues/6824