[Android] Fixed back button icon selection logic in ShellToolbarTracker

src/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellToolbarTracker.cs

@@ -416,8 +416,7 @@ protected virtual async void UpdateLeftBarButtonItem(Context context, AToolbar t
 			var command = backButtonHandler.GetPropertyIfSet<ICommand>(BackButtonBehavior.CommandProperty, null);
 			var backButtonVisibleFromBehavior = backButtonHandler.GetPropertyIfSet(BackButtonBehavior.IsVisibleProperty, true);
 			bool isEnabled = _shell.Toolbar.BackButtonEnabled;
-			//Add the FlyoutIcon only if the FlyoutBehavior is Flyout
-			var image = _flyoutBehavior == FlyoutBehavior.Flyout ? GetFlyoutIcon(backButtonHandler, page) : null;
+			var image = _flyoutBehavior == FlyoutBehavior.Flyout ? GetFlyoutIcon(backButtonHandler, page) : backButtonHandler.GetPropertyIfSet<ImageSource>(BackButtonBehavior.IconOverrideProperty, null);
 			var backButtonVisible = _toolbar.BackButtonVisible;
 
 			DrawerArrowDrawable icon = null;

src/Controls/tests/TestCases.HostApp/Issues/Issue32050.xaml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<Shell xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+       x:Class="Maui.Controls.Sample.Issues.Issue32050">
+
+    <ShellContent Title="Home">
+        <ContentPage>
+            <Label
+                Text="Issue 32050"
+                AutomationId="Label"
+                VerticalOptions="Center"
+                HorizontalOptions="Center"/>
+        </ContentPage>
+    </ShellContent>
+
+</Shell>

src/Controls/tests/TestCases.HostApp/Issues/Issue32050.xaml.cs

@@ -0,0 +1,21 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 32050, "IconOverride in Shell.BackButtonBehavior does not work.", PlatformAffected.iOS)]
+public partial class Issue32050 : Shell
+{
+	public Issue32050()
+	{
+		InitializeComponent();
+		Routing.RegisterRoute("Issue32050SubPage", typeof(Issue32050SubPage));
+		GoToAsync("Issue32050SubPage");
+	}
+
+	class Issue32050SubPage : ContentPage
+	{
+		public Issue32050SubPage()
+		{
+			Content = new Label { Text = "Label", AutomationId = "Label" };
+			SetBackButtonBehavior(this, new BackButtonBehavior { IconOverride = "coffee.png" });
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32050.cs

@@ -0,0 +1,22 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue32050 : _IssuesUITest
+{
+	public Issue32050(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "IconOverride in Shell.BackButtonBehavior does not work.";
+
+	[Test]
+	[Category(UITestCategories.TitleView)]
+	public void IconOverrideInShellBackButtonBehaviorShouldWork()
+	{
+		App.WaitForElement("Label");
+		VerifyScreenshot();
+	}
+}