fix blend.

src/Avalonia.Visuals/Media/ExperimentalAcrylicMaterial.cs

@@ -355,7 +355,7 @@ namespace Avalonia.Media
 
             var luminosityColor = new Color(255, Trim(lightness), Trim(lightness), Trim(lightness));
 
-            luminosityColor = Blend(luminosityColor, new Color((byte)Math.Round(255 * TintOpacity), TintColor.R, TintColor.G, TintColor.B));
+            luminosityColor = Blend(luminosityColor, new Color(255, TintColor.R, TintColor.G, TintColor.B));
 
             //var compensationMultiplier = 1 - PlatformTransparencyCompensationLevel;
             //return new Color((byte)(255 * Math.Max(Math.Min(PlatformTransparencyCompensationLevel + ( luminosityOpacity.Value * compensationMultiplier), 1.0), 0.0)), luminosityColor.R, luminosityColor.G, luminosityColor.B);