File being output twice (with and without project name in the path)

[Gavin-Williams]

I have some files that are being output twice to the output directory. Considering one of the files, it is set to

BuildAction = Content
Copy to Output Directory = Copy if newer

And the file is mentioned in the libraries csproj file as follows...
<Content Update="UI\Controls\Terminal\C64_16px1p.png"> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> </Content>

In the project that uses the library, why do I get 2 different copies of the file in its output directory? They have the following paths...

bin / debug / net8.0 / Framework / UI / Controls / Terminal / C64_16px1p.png
bin / debug / net8.0 / UI / Controls / Terminal / C64_16px1p.png

Likewise, there are two copies with the same folder structure in the library project as well. I deleted bin and obj before building. And this crazy folder structure was recreated.

I made a small test solution to try to reproduce this behavior, and I couldn't. It does what's expected and only produces a single file in the output. So whatever has happened here, may only occur in larger projects as a hidden consequence of work.

bin/ debug / net8.0 / UI / LibShader.hlsl // without the project name in the path.

Note: This becomes important, because as of yesterday VS has stopped respecting Copy-if-newer and Copy-always. It looks like one of the copies is being updated, but not the other one - not the one that is actually used. Which means builds aren't working. Because file changes aren't visible to my code when it loads hlsl files.

I want visual studio to only output a single copy, and keep it updated, so that I know where to load the file from in a way that isn't like rolling a dice for success or failure.

[Gavin-Williams]

I installed project system tools and recorded a build. Going down through it I found...

Target GetCopyToOutputDirectoryItemsOutputGroup Add GetCopyToOutputDirectoryItemsOutputGroupOutput

And a whole heap of items, including the example .png I mention here are listed twice with the two paths.

So what? I don't know. This just tells me that it's doing what I thought it was doing. It says the source file is:

C:\Users\deads.nuget\packages\microsoft.windowsappsdk\1.4.231219000\buildTransitive\MrtCore.PriGen.targets

And the parent is

GetMrtPackagingOutputs

[GangWang01]

Can you provide the binary log for investigation referring to https://github.com/dotnet/msbuild/blob/main/documentation/wiki/Providing-Binary-Logs.md if possible? Be aware of what information is included in the binary log before sharing.