Fix ContentPage memory leak on Android when using NavigationPage modally (fixes #33918)

src/Controls/src/Core/NavigationPage/NavigationPage.cs

@@ -838,7 +838,6 @@ await Owner.SendHandlerUpdateAsync(animated,
 						Owner.FireDisappearing(currentPage);
 						Owner.RemoveFromInnerChildren(currentPage);
 						Owner.CurrentPage = newCurrentPage;
-						Owner.RemoveFromInnerChildren(currentPage);
 						if (currentPage.TitleView != null)
 						{
 							currentPage.RemoveLogicalChild(currentPage.TitleView);

src/Controls/tests/DeviceTests/Elements/NavigationPage/NavigationPageTests.Android.cs

@@ -1,15 +1,18 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
 using Google.Android.Material.AppBar;
 using Microsoft.Maui;
 using Microsoft.Maui.Controls;
 using Microsoft.Maui.Controls.Handlers;
 using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Handlers;
 using Microsoft.Maui.Platform;
 using Xunit;
+using static Microsoft.Maui.DeviceTests.AssertHelpers;
 
 namespace Microsoft.Maui.DeviceTests
 {
@@ -47,5 +50,65 @@ await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async
 				Assert.False(failed);
 			});
 		}
+
+		[Fact(DisplayName = "StackNavigationManager Clears References On Disconnect (Issue 33918)")]
+		public async Task StackNavigationManagerClearsReferencesOnDisconnect()
+		{
+			SetupBuilder();
+
+			var mainPage = new ContentPage { Title = "Main Page" };
+			var baseNavPage = new NavigationPage(mainPage);
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(baseNavPage), async (handler) =>
+			{
+				var tab1Content = new ContentPage { Title = "Tab 1", Content = new Label { Text = "Tab 1 Content" } };
+				var tab2Content = new ContentPage { Title = "Tab 2", Content = new Label { Text = "Tab 2 Content" } };
+
+				var tab1Nav = new NavigationPage(tab1Content) { Title = "Tab 1" };
+				var tab2Nav = new NavigationPage(tab2Content) { Title = "Tab 2" };
+
+				var tabbedPage = new TabbedPage
+				{
+					Title = "Tabbed Modal",
+					Children = { tab1Nav, tab2Nav }
+				};
+
+				await baseNavPage.Navigation.PushModalAsync(tabbedPage, animated: false);
+				await OnLoadedAsync(tab1Content);
+
+				var tab1Handler = tab1Nav.Handler as NavigationViewHandler;
+				var tab2Handler = tab2Nav.Handler as NavigationViewHandler;
+				Assert.NotNull(tab1Handler);
+				Assert.NotNull(tab2Handler);
+
+				var tab1SnManager = tab1Handler.StackNavigationManager;
+				var tab2SnManager = tab2Handler.StackNavigationManager;
+				Assert.NotNull(tab1SnManager);
+				Assert.NotNull(tab2SnManager);
+
+				tabbedPage.CurrentPage = tab2Nav;
+				await OnLoadedAsync(tab2Content);
+
+				await baseNavPage.Navigation.PopModalAsync(animated: false);
+
+				var flags = BindingFlags.NonPublic | BindingFlags.Instance;
+				var currentPageField = typeof(StackNavigationManager).GetField("_currentPage", flags);
+				var fragmentContainerViewField = typeof(StackNavigationManager).GetField("_fragmentContainerView", flags);
+				var fragmentManagerField = typeof(StackNavigationManager).GetField("_fragmentManager", flags);
+
+				Assert.NotNull(currentPageField);
+				Assert.NotNull(fragmentContainerViewField);
+				Assert.NotNull(fragmentManagerField);
+
+				await AssertEventually(() =>
+					currentPageField.GetValue(tab1SnManager) == null &&
+					fragmentContainerViewField.GetValue(tab1SnManager) == null &&
+					fragmentManagerField.GetValue(tab1SnManager) == null &&
+					currentPageField.GetValue(tab2SnManager) == null &&
+					fragmentContainerViewField.GetValue(tab2SnManager) == null &&
+					fragmentManagerField.GetValue(tab2SnManager) == null,
+					message: "StackNavigationManager fields were not cleared after Disconnect()");
+			});
+		}
 	}
 }

src/Controls/tests/DeviceTests/Memory/MemoryTests.cs

@@ -99,10 +99,8 @@ void SetupBuilder()
 
 	[Theory("Pages Do Not Leak")]
 	[InlineData(typeof(ContentPage))]
-#if !ANDROID
 	[InlineData(typeof(NavigationPage))]
-	//https://github.com/dotnet/maui/issues/27411
-#endif
+	// Issue #27411 (partially) and #33918 have been fixed - NavigationPage no longer leaks on Android
 	[InlineData(typeof(TabbedPage))]
 	public async Task PagesDoNotLeak([DynamicallyAccessedMembers(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] Type type)
 	{

src/Core/src/Platform/Android/Navigation/StackNavigationManager.cs

@@ -317,6 +317,10 @@ public virtual void Disconnect()
 			NavigationView = null;
 			SetNavHost(null);
 			_fragmentNavigator = null;
+			_currentPage = null;
+			NavigationStack = [];
+			_fragmentContainerView = null;
+			_fragmentManager = null;
 		}
 
 		public virtual void Connect(IView navigationView)