This is an excellent question, and I don't know the answer. The behaviour you describe is surprising, at least to me. The development version of perl exhibits the same behaviour. I wonder whether this is a known limitation, because there is a warning in perlfunc: 
Though if you try to re-open C<STDOUT> or C<STDERR> as an "in memory"
file, you have to close it first:

    close STDOUT;
    open STDOUT, '>', \$variable or die "Can't open STDOUT: $!";

[download]
Of course this isn't talking about encodings, but I think it might be the same problem. Unless a PerlIO guru pops up here, I'd suggest asking p5p.

PS. If you just want a minimal demonstration script, you can delete most of your code: 

# close STDOUT;  # with this it works
open STDOUT, ">:encoding(cp37)", "foo.out" or die "Cannot redirect STD
+OUT\n";
print "yadda yadda\n";

[download]

In reply to Re: Redirection and encoding, broken or WAD? by robin
in thread Redirection and encoding, broken or WAD? by BillSeurer

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.