APPX1111/APPX1112 when attempting to build a separate project with XAML and packaging with a WAP project

[Tech5G5G]

Describe the bug

In my solution, I have three projects: Project, Project.UI, and Project (Package). Project is my main WinUI project, Project (Package) is my Windows Application Packaging Project, and Project.UI is a WinUI Class Library that contains some generic controls. Project.UI is referenced and used by Project. Similarly, Project is referenced by and is the entry point of Project (Package).

Whenever I modify the XAML of a control in Project.UI and attempt to build Project (Package), I get an error stating:

Payload contains two or more files with the same destination path 'Project.UI\Control.xbf', but they are different sizes.

with paths to two of the same file: Control.xbf; but indeed with different contents and thus sizes.

Building Project (Package) again, the error disappears and I am then able to launch my application. Attempting to modify the XAML of the control again results in more of the same.

Is there a property in one of my three projects that I'm missing? Or is this about something else?

Why is this important?

I would like to immediately start and test my application without any unsolvable errors.

Steps to reproduce the bug

1. Create a WinUI Blank App (Packaged with Windows Application Packaging Project) named e.g. Project.
2. Add a WinUI Class Library to the solution named e.g. Project.UI.
3. Optionally delete Class1.cs.
4. To the WinUI Class Library, add a User Control named e.g. Control.
5. Add a reference to the WinUI Class Library from the WinUI Blank App.
6. Build the Windows Application Packaging Project.
7. Modify the User Control (e.g. replace the Grid with a StackPanel, set Background to Red).
8. Build the Windows Application Packaging Project again.
9. Observe APPX1111 (or APPX1112) in all of its glory.

Actual behavior

A build error occurs stating there is a contradictory duplicate of e.g. Control.xbf whenever I update e.g. Control.xaml.

Expected behavior

Compilation and packaging should complete without any inconsistent duplicate file errors.

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.8.3: 1.8.251106002

Windows version

Windows Insider Build (xxxxx)

Additional context

I also have a UWP Windows Runtime Component in my solution, which is referenced by Project. It contains an implementation of IBackgroundTask that is used as an app service via WinRT.Host.dll (as demonstrated here), but it appears to be unrelated to this issue.

[Tech5G5G]

As a workaround, adding

<DisableEmbeddedXbf>false</DisableEmbeddedXbf>

to the library containing XAML (in my case, Project.UI) resolves the issue. I'm not sure what implications adding this property has for other parts of WinUI, but It Works On My Machine™.