MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="ShellTabsUnloadedBug.MainPage">

    <Grid RowDefinitions="*, *">
        <Label Grid.Row="0"
               Text="To reproduce: Run on Android, Press button below, Press second tab, Press first tab. Watch debug output: Unloaded event fires when SecondPage appears, but it hasn't been unloaded yet."
               HorizontalOptions="Center"
               VerticalOptions="Center" />

        <Button Grid.Row="1"
                Text="Open SecondPage"
                HorizontalOptions="Center"
                VerticalOptions="Center"
                Clicked="Button_OnClicked" />
    </Grid>

</ContentPage>