ImageResourceExtension gives an System.PlatformNotSupportedException in UWP release

Description

Xamarin.Forms sample you can use to recreate the problem is: https://github.com/xamarin/xamarin-forms-samples/XAML/MarkupExtensions This problem does not appear with the UWP debug version of the sample app. If you compile and run this sample for UWP release, select Image Resource Demo. You will immediately break with a System.PlatformNotSupportedException. This will happen with any sample using this extension. And this includes any of the Xamarin-Forms-Book-Samples using the ImageResourceExtension.cs.

Steps to Reproduce

If you compile and run the sample described above for UWP release, then select the Image Resource Demo. You will immediately break with a System.PlatformNotSupportedException. The error occurs at the following line: return ImageSource.FromResource(assemblyName + "." + Source); The source is an embedded image.

Expected Behavior

Actual Behavior

Basic Information

• Version with issue:
• Last known good version: I don't know. I discovered the problem while trying to compile a Xamarin.Forms book sample and then again when I tried to compile a Xamarin.forms sample.
• IDE:
• Platform Target Frameworks: Xamarin.Forms Version=3.3.0.967583 UWP version : 10.0.17134.0
  • iOS:
  • Android:
  • UWP:
• Android Support Library Version:
• Nuget Packages:
• Affected Devices:

Screenshots

Reproduction Link