[Android] Fix CollectionView dynamic item sizing reset after scroll

src/Controls/src/Core/Handlers/Items/Android/TemplatedItemViewHolder.cs

@@ -43,13 +43,10 @@ public void Recycle(ItemsView itemsView)
 
 			itemsView.RemoveLogicalChild(View);
 
-			// Disconnect and clear the handler via ItemContentView.Recycle(), which calls
-			// DisconnectHandlers() before releasing Content. Reset _selectedTemplate so the
-			// next Bind() call always goes through the templateChanging path and recreates
-			// the handler (since we just disconnected it).
+			// Disconnect the current handler and release the platform content. We keep the
+			// existing View/_selectedTemplate references so the next Bind() can decide whether
+			// it needs to re-realize the same templated view or create a new one.
 			_itemContentView.Recycle();
-			View = null; // clear reference to the disconnected view
-			_selectedTemplate = null; // force templateChanging=true on next Bind() to recreate the view
 		}
 
 		public void Bind(object itemBindingContext, ItemsView itemsView,
@@ -90,8 +87,16 @@ public void Bind(object itemBindingContext, ItemsView itemsView,
 
 			if (!templateChanging)
 			{
-				// Same template, new data
+				// Same template — update binding context. If the handler was disconnected
+				// during recycle, re-realize the existing view to reconnect platform content
+				// without losing any runtime property changes (e.g. dynamic HeightRequest).
 				View.BindingContext = itemBindingContext;
+
+				if (View?.Handler is null)
+				{
+					PropertyPropagationExtensions.PropagatePropertyChanged(null, View, itemsView);
+					_itemContentView.RealizeContent(View, itemsView);
+				}
 			}
 
 			itemsView.AddLogicalChild(View);

src/Controls/tests/TestCases.HostApp/Issues/Issue34783.cs

@@ -0,0 +1,136 @@
+using System.Collections.ObjectModel;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 34783, "CollectionView Dynamic item sizing - After dragging the scrollbar all images return to their original size", PlatformAffected.Android)]
+public class Issue34783 : ContentPage
+{
+	public Issue34783()
+	{
+		BindingContext = new Issue34783ViewModel();
+
+		var grid = new Grid
+		{
+			Margin = new Thickness(20),
+			RowDefinitions = new RowDefinitionCollection
+			{
+				new RowDefinition { Height = GridLength.Auto },
+				new RowDefinition { Height = GridLength.Auto },
+				new RowDefinition { Height = GridLength.Star }
+			}
+		};
+
+		var instructions = new StackLayout
+		{
+			Children =
+			{
+				new Label { Text = "1.Confirm that the CollectionView below is populated with monkeys and can be scrolled." },
+				new Label { Text = "2.The test passes if tapping each image dynamically changes its size." }
+			}
+		};
+
+		var tapLabel = new Label { Text = "Tap each image to dynamically change its size." };
+
+		var itemTemplate = new DataTemplate(() =>
+		{
+			var innerGrid = new Grid { Padding = new Thickness(10) };
+			innerGrid.RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
+			innerGrid.RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
+			innerGrid.ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Auto });
+			innerGrid.ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Star });
+
+			var image = new Image
+			{
+				Aspect = Aspect.AspectFill,
+				HeightRequest = 60,
+				WidthRequest = 60
+			};
+			image.SetBinding(Image.SourceProperty, new Binding("ImageUrl"));
+			image.SetBinding(Image.AutomationIdProperty, new Binding("Name"));
+
+			var tapGesture = new TapGestureRecognizer();
+			tapGesture.Tapped += OnImageTapped;
+			image.GestureRecognizers.Add(tapGesture);
+
+			Grid.SetRowSpan(image, 2);
+
+			var nameLabel = new Label { FontAttributes = FontAttributes.Bold };
+			nameLabel.SetBinding(Label.TextProperty, new Binding("Name"));
+			Grid.SetColumn(nameLabel, 1);
+
+			var locationLabel = new Label
+			{
+				FontAttributes = FontAttributes.Italic,
+				VerticalOptions = LayoutOptions.End
+			};
+			locationLabel.SetBinding(Label.TextProperty, new Binding("Location"));
+			Grid.SetRow(locationLabel, 1);
+			Grid.SetColumn(locationLabel, 1);
+
+			innerGrid.Children.Add(image);
+			innerGrid.Children.Add(nameLabel);
+			innerGrid.Children.Add(locationLabel);
+
+			return innerGrid;
+		});
+
+		var collectionView = new CollectionView
+		{
+			AutomationId = "Issue34783CollectionView",
+			ItemTemplate = itemTemplate
+		};
+		collectionView.SetBinding(CollectionView.ItemsSourceProperty, new Binding("Monkeys"));
+
+		Grid.SetRow(tapLabel, 1);
+		Grid.SetRow(collectionView, 2);
+
+		grid.Children.Add(instructions);
+		grid.Children.Add(tapLabel);
+		grid.Children.Add(collectionView);
+
+		Content = grid;
+	}
+
+	void OnImageTapped(object sender, EventArgs e)
+	{
+		if (sender is Image image)
+			image.HeightRequest = image.WidthRequest = image.HeightRequest.Equals(60) ? 100 : 60;
+	}
+}
+
+public class Issue34783Monkey
+{
+	public string Name { get; set; }
+	public string Location { get; set; }
+	public string Details { get; set; }
+	public string ImageUrl { get; set; }
+}
+
+public class Issue34783ViewModel
+{
+	public ObservableCollection<Issue34783Monkey> Monkeys { get; set; }
+
+	public Issue34783ViewModel()
+	{
+		Monkeys = new ObservableCollection<Issue34783Monkey>
+		{
+			new Issue34783Monkey { Name = "Baboon",               Location = "Africa & Asia",               ImageUrl = "papio.jpg" },
+			new Issue34783Monkey { Name = "Capuchin Monkey",      Location = "Central & South America",     ImageUrl = "capuchin.jpg" },
+			new Issue34783Monkey { Name = "Blue Monkey",          Location = "Central and East Africa",     ImageUrl = "bluemonkey.jpg" },
+			new Issue34783Monkey { Name = "Squirrel Monkey",      Location = "Central & South America",     ImageUrl = "saimiri.jpg" },
+			new Issue34783Monkey { Name = "Golden Lion Tamarin",  Location = "Brazil",                      ImageUrl = "golden.jpg" },
+			new Issue34783Monkey { Name = "Howler Monkey",        Location = "South America",               ImageUrl = "alouatta.jpg" },
+			new Issue34783Monkey { Name = "Japanese Macaque",     Location = "Japan",                       ImageUrl = "papio.jpg" },
+			new Issue34783Monkey { Name = "Mandrill",             Location = "Central Africa",              ImageUrl = "capuchin.jpg" },
+			new Issue34783Monkey { Name = "Proboscis Monkey",     Location = "Borneo",                      ImageUrl = "bluemonkey.jpg" },
+			new Issue34783Monkey { Name = "Red-shanked Douc",     Location = "Vietnam, Laos",               ImageUrl = "saimiri.jpg" },
+			new Issue34783Monkey { Name = "Gray-shanked Douc",    Location = "Vietnam",                     ImageUrl = "golden.jpg" },
+			new Issue34783Monkey { Name = "Snub-nosed Monkey",    Location = "China",                       ImageUrl = "alouatta.jpg" },
+			new Issue34783Monkey { Name = "Black Snub-nosed",     Location = "China",                       ImageUrl = "papio.jpg" },
+			new Issue34783Monkey { Name = "Tonkin Monkey",        Location = "Vietnam",                     ImageUrl = "capuchin.jpg" },
+			new Issue34783Monkey { Name = "Thomas Langur",        Location = "Indonesia",                   ImageUrl = "bluemonkey.jpg" },
+			new Issue34783Monkey { Name = "Purple-faced Langur",  Location = "Sri Lanka",                   ImageUrl = "saimiri.jpg" },
+			new Issue34783Monkey { Name = "Gelada",               Location = "Ethiopia",                    ImageUrl = "golden.jpg" },
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue34783.cs

@@ -0,0 +1,48 @@
+#if TEST_FAILS_ON_CATALYST // Issue34783 is flaky on MacCatalyst due to non-deterministic scroll-recycle timing.
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue34783 : _IssuesUITest
+{
+	public override string Issue => "CollectionView Dynamic item sizing - After dragging the scrollbar all images return to their original size";
+
+	public Issue34783(TestDevice device) : base(device) { }
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void ImagesKeepSizeAfterScrolling()
+	{
+		// Wait for the CollectionView to load; first item "Baboon" image is used as the anchor
+		App.WaitForElement("Baboon");
+
+		// Record the initial rendered height of the first image (should be ~60)
+		var initialRect = App.WaitForElement("Baboon").GetRect();
+
+		// Tap the first image to enlarge it (60 → 100) using coordinates to reliably
+		// hit the Image element (which has a TapGestureRecognizer, not a Button click)
+		App.TapCoordinates(initialRect.X + initialRect.Width / 2, initialRect.Y + initialRect.Height / 2);
+
+		// Confirm the image has grown
+		var enlargedRect = App.WaitForElement("Baboon").GetRect();
+		Assert.That(enlargedRect.Height, Is.GreaterThan(initialRect.Height),
+			"Image should be enlarged after tap");
+
+		// Scroll down to push the first item off screen (simulates dragging the scrollbar,
+		// which triggers RecyclerView item recycling on Android)
+		App.ScrollDown("Issue34783CollectionView", ScrollStrategy.Gesture, 0.9);
+
+		// Scroll back up to bring Baboon back into view
+		App.ScrollUp("Issue34783CollectionView", ScrollStrategy.Gesture, 0.9);
+		App.ScrollUp("Issue34783CollectionView", ScrollStrategy.Gesture, 0.9);
+
+		// Verify the image is still at the enlarged size and was not reset to the original
+		App.WaitForElement("Baboon");
+		var afterScrollRect = App.WaitForElement("Baboon").GetRect();
+		Assert.That(afterScrollRect.Height, Is.GreaterThan(initialRect.Height),
+			"Image should keep its enlarged size after scrolling; resetting to original size is the bug");
+	}
+}
+#endif