https://bugs.winehq.org/show_bug.cgi?id=54194
--- Comment #4 from Esme Povirk madewokherd@gmail.com --- It's possible that in later versions it silently fails to send to higher-integrity processes in the case of broadcast. You could always test by running an elevated notepad or something yourself.
I don't see how you would identify a specific window that caused the error.