https://bugs.winehq.org/show_bug.cgi?id=49852
--- Comment #6 from Rafał Mużyło galtgendo@o2.pl --- wrt. those differences between redirecting to /dev/null and a pipe, I'd like to mention again (previously mentioned either in chat or a bug I no longer recall) a tangentially related problem:
I ran into a Unity game that crashed due to address space exhaustion. While it was in the process of crashing, it was producing error messages containing mojibake. Yet if it was redirected via tee, those errors strings were correctly printed. So, this might be another part that needs checking.