Fix for Control does not update from binding anymore after MultiBinding.ConvertBack is called

src/Controls/src/Core/MultiBinding.cs

@@ -105,7 +105,8 @@ internal override void Apply(bool fromTarget)
 						BindingDiagnostics.SendBindingFailure(this, null, _targetObject, _targetProperty, "MultiBinding", BindingExpression.CannotConvertTypeErrorMessage, value, _targetProperty.ReturnType);
 						return;
 					}
-					_targetObject.SetValueCore(_targetProperty, value, SetValueFlags.ClearDynamicResource, BindableObject.SetValuePrivateFlags.Default | BindableObject.SetValuePrivateFlags.Converted, specificity: SetterSpecificity.FromBinding);
+					// ManualValueSetter specificity ensures TwoWay bindings continue updating after ConvertBack.
+					_targetObject.SetValueCore(_targetProperty, value, SetValueFlags.ClearDynamicResource, BindableObject.SetValuePrivateFlags.Default | BindableObject.SetValuePrivateFlags.Converted, specificity: SetterSpecificity.ManualValueSetter);
 					_applying = false;
 				}
 			}

src/Controls/tests/Core.UnitTests/MultiBindingTests.cs

@@ -55,6 +55,49 @@ public void TestChildOneWayOnMultiTwoWay()
 			Assert.Equal($"{oldFirstName} {oldMiddleName} {oldLastName.ToUpperInvariant()}", group.Person1.FullName);
 		}
 
+		[Fact]
+		public void TestMultiBindingContinuesUpdatingAfterConvertBack()
+		{
+			var group = new GroupViewModel();
+			var stack = new StackLayout
+			{
+				BindingContext = group.Person1
+			};
+
+			var label = new Label();
+			label.SetBinding(Label.TextProperty, new MultiBinding
+			{
+				Bindings = new Collection<BindingBase>
+				{
+					new Binding(nameof(PersonViewModel.FirstName)),
+					new Binding(nameof(PersonViewModel.MiddleName)),
+					new Binding(nameof(PersonViewModel.LastName)),
+				},
+				Converter = new StringConcatenationConverter(),
+				Mode = BindingMode.TwoWay,
+			});
+			stack.Children.Add(label);
+
+			string originalName = "Gaius Julius Caesar";
+			Assert.Equal(originalName, label.Text);
+
+			label.Text = "Marcus Tullius Cicero";
+
+			Assert.Equal("Marcus", group.Person1.FirstName);
+			Assert.Equal("Tullius", group.Person1.MiddleName);
+			Assert.Equal("Cicero", group.Person1.LastName);
+			Assert.Equal("Marcus Tullius Cicero", label.Text);
+
+			group.Person1.FirstName = "Julius";
+
+			Assert.Equal("Julius Tullius Cicero", label.Text);
+			Assert.Equal("Julius Tullius Cicero", group.Person1.FullName);
+
+			group.Person1.LastName = "Augustus";
+			Assert.Equal("Julius Tullius Augustus", label.Text);
+			Assert.Equal("Julius Tullius Augustus", group.Person1.FullName);
+		}
+
 		[Fact]
 		public void TestRelativeSources()
 		{