HandlerFunction does not call ModalPageHandler?!

Hey guys,

I discovered a new error in my test codeunit.

For me it is not possible that the HandlerFunction calls the ModalPageHandler...

I also used the Debugger in Visual Studio Code, but it did not help me either.

I have seen that the reference under ModalPageHandler is zero, maybe this has something to do with my problem...

Do you see my mistake/-s?