https://bugs.winehq.org/show_bug.cgi?id=41269
--- Comment #33 from Hans Leidekker hans@meelstraat.net --- (In reply to Reinhold from comment #31)
May be it is a new bug. I am glad you got it.
Yes, that's bug number 4. Your test installer shows that a custom action failure should trigger a rollback too. It doesn't happen on Wine.