in reply to
Re^4: Standard handles inherited from a utf-8 enabled shell
in thread Standard handles inherited from a utf-8 enabled shell
I speculate that if you print bytes with the high-bit set, from a no-utf-enabled instance of perl, run from a utf-enabled shell, this situation can arise. Regardless of the OS you happen to be running on.
I won't believe this until I've seen it, reproduced as a minimal example (disregarding things like shell alises that add command line options, PERL5OPT, PERLIO or PERL_UNICODE environment variables).