The outcomes dictionary that is passed to the CreateOutcome method has its key set to a string with ToLower() instead of having a case-insensitive comparer. As a result, instead of notExecuted, we get notexecuted, which Visual Studio 2022 is complaining about and not accepting:
<ResultSummary outcome="Completed" xmlns="http://microsoft.com/schemas/VisualStudio/TeamTest/2010">
<Counters total="5" passed="1" failed="0" notexecuted="4" />
</ResultSummary>
It is also worth questioning whether the case insensitivity is actually warranted in this case.