I noticed the same thing recently, under Perl v5.8.8.

I use decode_utf8 in a custom override of CGI's param() method, to give me properly flagged unicode strings. When I installed Encode 2.08, file uploads broke, because the incoming file handles got mangled. I fixed this issue inside my custom param() method, but I suppose you could also brute-force the issue by overriding decode_utf8:

{
    no warnings 'redefine';

    my $decode_utf8_orig = \&Encode::decode_utf8;

    *Encode::decode_utf8 = sub {
        return $_[0] if ref $_[0];     # avoid mangling references.
        goto &$decode_utf8_orig;       # original behavior for normal 
+scalars.
    }
}
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