Use ReflectionBinding instead of x:CompileBindings="False".

src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml

@@ -159,9 +159,8 @@
               </ContentPresenter.DataTemplates>
             </ContentPresenter>
             <Popup Name="PART_Popup"
-                   x:CompileBindings="False"
                    WindowManagerAddShadowHint="False"
-                   MinWidth="{Binding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
+                   MinWidth="{ReflectionBinding Bounds.Width, RelativeSource={RelativeSource TemplatedParent}}"
                    IsLightDismissEnabled="True"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}"
                    OverlayInputPassThroughElement="{Binding $parent[Menu]}">

src/Avalonia.Themes.Fluent/Controls/ProgressBar.xaml

@@ -32,7 +32,7 @@
                 <Border x:Name="IndeterminateProgressBarIndicator2" CornerRadius="{TemplateBinding CornerRadius}" Margin="{TemplateBinding Padding}" Background="{TemplateBinding Foreground}" />
               </Panel>
               <LayoutTransformControl x:Name="PART_LayoutTransformControl" HorizontalAlignment="Center" VerticalAlignment="Center" IsVisible="{TemplateBinding ShowProgressText}">
-                <TextBlock x:CompileBindings="False" Foreground="{DynamicResource SystemControlForegroundBaseHighBrush}" Text="{Binding Value, RelativeSource={RelativeSource TemplatedParent}, StringFormat={}{0:0}%}" />
+                <TextBlock Foreground="{DynamicResource SystemControlForegroundBaseHighBrush}" Text="{ReflectionBinding Value, RelativeSource={RelativeSource TemplatedParent}, StringFormat={}{0:0}%}" />
               </LayoutTransformControl>
             </Panel>
         </Border>