The '-encoding' attribute sets the encoding in the XML declaration, not as a META element. To get that, you'd use this (which is pretty ugly but works):

my $q = CGI->new();

print $q->header(-charset => 'utf-8'),
    $q->start_html(
        -encoding => 'utf-8',
        -head     => $q->meta({
            -http_equiv => 'Content-Type',
            -content    => 'text/html; charset=utf-8'
        })
    );
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