Xamarin.forms Shell page freezing on some devices

Question

I developed an xamarin.forms app that used to work very well wheh testings with testflight. I have now posted it on the app store and I get a strange bug on the phones that had never had the testflight app installed.

I have a tab bar with 2 buttons (my main page and a About page):

The problem occurs when user click on AboutPage button in tab bar. Tha app hangs/freezes forever. The page is selected in the tab bar but the ui never appears

From the main page if a user navigates to any other page in the app it works well.

On my phone I don't have the problem and so it's very hard to debug.

AppShell.xaml:

<Shell xmlns="http://xamarin.com/schemas/2014/forms" 
       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
       xmlns:local="clr-namespace:AApplicationX.Views"
       xmlns:General="clr-namespace: ApplicationX.Views.General"
       x:Class="ApplicationX.AppShell">
    <TabBar>
        <ShellContent Title="Menu" Icon="home.png" ContentTemplate="{DataTemplate General:HomePage}" />
        <ShellContent Title="About" Icon="icon_about.png"  ContentTemplate="{DataTemplate General:AboutPage}" />
    </TabBar>
</Shell>

AppShell.xaml.cs

public partial class AppShell : Xamarin.Forms.Shell
{
   public AppShell()
   {
      InitializeComponent();

      Routing.RegisterRoute(nameof(AboutPage), typeof(AboutPage));
      Routing.RegisterRoute(nameof(CalibreCableView), typeof(CalibreCableView));
...
    }
}