"Could not copy the file ..." errors after adding Microsoft.WindowsAppSDK.ML NuGet package

Describe the bug

I've created a project following these instructions:
https://www.nuget.org/packages/Microsoft.WindowsAppSDK.ML/

If I build the project, it fails with below "Could not copy the file ..." error.

If I change 'Content Include="myIcon.ico"' to 'Content Update="myIcon.ico"' inside Business.csproj the project does build.

Adding a simple NuGet package (Microsoft.WindowsAppSDK.ML) should not mess up my build, and it should not want to copy my files from non-existing places.

Steps to reproduce the bug

1. Install VisualStudio 2026 and .net10
2. Unzip attached file
3. Run this in x64 command prompt (or build with VisualStudio)
   msbuild TestWindowsAppSdk.sln /p:Configuration=Debug /p:Platform="Any CPU" /t:build -restore

Error (full output attached):
C:\Program Files\Microsoft Visual Studio\18\Community\MSBuild\Current\Bin\amd64\Microsoft.Common.CurrentVersion.targets
(5381,5): error MSB3030: Could not copy the file "C:\codeother\TestWindowsAppSdk2\Business\bin\Debug\net10.0-windows10.
0.17763.0\Business\myIcon.ico" because it was not found. [C:\codeother\TestWindowsAppSdk2\Main\Main.csproj]

TestWindowsAppSdk2.zip

msbuild-output.txt

Expected behavior

Project should just build when adding Microsoft.WindowsAppSDK.ML NuGet.

Screenshots

No response

NuGet package version

Windows App SDK 1.8.4: 1.8.260101001

Packaging type

Unpackaged

Windows version

Windows 11 version 24H2 LTSC (26100, June Update)

IDE

Other

Additional context

No response

Start with the attached TestWindowsAppSdk solution, especially Business.csproj and Main.csproj, and reproduce the build using the listed msbuild command. Compare the Content Include entry for myIcon.ico with the Content Update workaround and inspect the package-related build output around Microsoft.Common.CurrentVersion.targets. Done means the unpackaged project builds successfully after adding Microsoft.WindowsAppSDK.ML without manually changing the project entry.