Custom ShareProvider does not show in share panel

[jschroedl]

Which sample are you reporting a bug in?

Example: ShareSource

Describe the bug
The custom "Contoso Chat" ShareProvider does not appear in the list of share targets.

Run the ShareSource sample on Windows 11 24H2 and select "9) Share with custom provider". The share sheet will show but there is no entry for "Contoso Chat".

If I debug, when stepping in this code, the msvsmon process will terminate.

https://github.com/microsoft/Windows-universal-samples/blob/082195895276903b6630d5cb4d03c9d365ec210c/Samples/ShareSource/cpp/ShareCustomProvider.xaml.cpp#L69C5-L69C6

To Reproduce
Steps to reproduce the behavior:

1. Build and run the ShareSource sample on Win11 24H2.
2. Click on 9) Share with custom provider
3. The share panel will display but Contoso Chat is not listed as a target.

Expected behavior
I expected to see Contoso Chat as a share target.

Screenshots

Configuration

• Language/architecture/flavor: C# Debug and C++/CX Debug.
• Windows platform and build number: Windows 11 Enterprise 24H2 build 26100.4969
• Visual Studio version: 17.14.11

Additional context
It's feasible that the OS now ignores the custom share providers but I cannot find any announcements of that. I would like to see code for a working custom provider before I try to add one to my app. I read about them here: https://blogs.windows.com/windowsdeveloper/2017/04/06/new-share-experience-windows-10-creators-update/