Why does a BITS background copy job (downloading a file) transition immediately into BG_JOB_STATE_TRANSIENT_ERROR for MSIX apps?

Question

I have an app using BITS to download files. When I packaged my app with MSIX, it started behaving strangely. Every background copy job started from the packaged app transitions into the BG_JOB_STATE_TRANSIENT_ERROR state immediately and stays that way until the app is closed or becomes inactive/minimized. This behavior is still unclear.

Using bitsadmin /list /allusers /verbose, I got this:

GUID: {A8C6001C-182D-424B-86DC-6C8E131E185B} DISPLAY: 'Download an update'
TYPE: DOWNLOAD STATE: TRANSIENT_ERROR OWNER: ....
PRIORITY: NORMAL FILES: 0 / 1 BYTES: 0 / UNKNOWN
CREATION TIME: 9/2/2022 11:33:08 AM MODIFICATION TIME: 9/2/2022 11:33:58 AM
COMPLETION TIME: UNKNOWN ACL FLAGS:
NOTIFY INTERFACE: UNREGISTERED NOTIFICATION FLAGS: 3
RETRY DELAY: 600 NO PROGRESS TIMEOUT: 1209600 ERROR COUNT: 0
PROXY USAGE: PRECONFIG PROXY LIST: NULL PROXY BYPASS LIST: NULL
ERROR FILE:    ...
ERROR CODE:    0x8020006e - The background access settings of the job's owner app prevent the job from transferring at this time.
ERROR CONTEXT: 0x00000002 - The error occurred in the Background Intelligent Transfer Service (BITS) queue manager.
DESCRIPTION:
JOB FILES:
        0 / UNKNOWN WORKING ...
NOTIFICATION COMMAND LINE: none
owner MIC integrity level: MEDIUM
owner elevated ?           false

Peercaching flags
         Enable download from peers      :false
         Enable serving to peers         :false

CUSTOM HEADERS: NULL

I tried to set the job's priority, but it didn't help. I also had a hunch that I might need to enable some capability in the MSIX manifest, but I haven't found anything. I also tried to use the BackgroundDownloader from my WPF app, but it looks like UWP only.

Is it a known behavior? Anything I can do to make it transfer bites while the packaged app is running?

My code:

• it's based on BITS-Manager
• it works great if the app is not pacakged
• I was able to reproduce the same behavior with BITS-Manager as well

internal class DownloadJob : BITS.IBackgroundCopyCallback
{
    private readonly TaskCompletionSource taskCompletionSource;
    private BITS.IBackgroundCopyJob job;

    public DownloadJob()
    {
        this.taskCompletionSource = new TaskCompletionSource();
        this.job = null;
    }

    public Task Start(string name, string url, string path, Action<byte[]> onJobIdCreated)
    {
        try
        {
            var manager = new BITS.BackgroundCopyManager1_5();
            GUID jobGuid;
            manager.CreateJob(
                name,
                BITS.BG_JOB_TYPE.BG_JOB_TYPE_DOWNLOAD,
                out jobGuid,
                out job);

            onJobIdCreated(jobGuid.GetBytes()); 

            job.AddFile(url, path);
            job.SetDownloadCost(Costs.TRANSFER_STANDARD);
            job.DisablePeerCaching();
            this.RegisterListenerFor(job);
            job.Resume();
        }
        catch
        {
            job?.Cancel();
            taskCompletionSource.TrySetException(new DownloadFailedException());
        }

        return taskCompletionSource.Task;
    }

    public void JobTransferred(BITS.IBackgroundCopyJob job)
    {
        job?.Complete();
        taskCompletionSource.TrySetResult();
    }

    public void JobError(BITS.IBackgroundCopyJob job, BITS.IBackgroundCopyError error)
    {
        job?.Cancel();
        taskCompletionSource.TrySetException(new DownloadFailedException());
    }

    public void JobModification(BITS.IBackgroundCopyJob pJob, uint dwReserved)
    {
    }
}

The packaging manifest:

<?xml version="1.0" encoding="utf-8"?>

<Package
  xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10"
  xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10"
  xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"
  IgnorableNamespaces="uap rescap">

  <Identity
    Name="..."
    Publisher="..."
    Version="1.0.0.0" />

  <Properties>
    <DisplayName>BITSManagerPackaged</DisplayName>
    <PublisherDisplayName>...</PublisherDisplayName>
    <Logo>Images\StoreLogo.png</Logo>
  </Properties>

  <Dependencies>
    <TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.0.0" MaxVersionTested="10.0.0.0" />
    <TargetDeviceFamily Name="Windows.Desktop" MinVersion="10.0.14393.0" MaxVersionTested="10.0.14393.0" />
  </Dependencies>

  <Resources>
    <Resource Language="x-generate"/>
  </Resources>

  <Applications>
    <Application Id="App"
      Executable="$targetnametoken$.exe"
      EntryPoint="$targetentrypoint$">
      <uap:VisualElements
        DisplayName="BITSManagerPackaged"
        Description="BITSManagerPackaged"
        BackgroundColor="transparent"
        Square150x150Logo="Images\Square150x150Logo.png"
        Square44x44Logo="Images\Square44x44Logo.png">
        <uap:DefaultTile Wide310x150Logo="Images\Wide310x150Logo.png" />
        <uap:SplashScreen Image="Images\SplashScreen.png" />
      </uap:VisualElements>
    </Application>
  </Applications>

  <Capabilities>
    <Capability Name="internetClient" />
    <rescap:Capability Name="runFullTrust" />
  </Capabilities>
</Package>