Hi Ralf Frotscher,
This behavior is usually caused by the Phone Web profile using a different page routing mechanism compared to desktop browsers. In Phone Web, Mendix often reinitializes the home page for anonymous users instead of respecting deep links or browser history states. Because of that, the URL step is ignored and the app jumps back to the default entry page.
You can fix this by enabling Deep Link / URL routing support for anonymous users in the Phone Web profile and making sure the target page is accessible without authentication. Also verify that navigation rules for Phone Web are not redirecting anonymous users to the home page automatically. Once URL parameters are allowed and routing is consistent, the correct step page will reload based on the exact URL.