https://bugs.winehq.org/show_bug.cgi?id=50894
--- Comment #2 from Roman Pišl rpisl@seznam.cz --- Ok, thanks, I don't know much about sys* redirections and native/builtin differences. Let's keep this about the regression for the builtin rundll32 binary, since this is the case and as I understand, it is a common way for a 32 bit application to run a 64bit code.
Since there is a workaround it is not a critical problem. Its only side-effect is that sysnative is also present in 64bit Wine but it does not exist in 64bit Windows.