I tried it with a different twist, using perl-5.17.2: 
#!/usr/bin/perl

BEGIN {
    $|  = 1;
    $^W = 1;
}

use autodie;
use strictures 1;
use common::sense;

open my $PL, '>', 'utf2.pl' or die $!;
print {$PL} << '__PL__';

binmode STDIN, ":utf8";
binmode STDOUT, ":encoding(UTF-8)";

while (defined(my $line = <ARGV>)) {
    if (my($word) = $line =~ /^(.+)$/) {
        my $one = substr($word, 0, 1); 
        my $w_one = substr($word, 0, 1);
        print  "'$one' = 'one'\t at $line" if $one eq $1;
        print "'$w_one' = 'w_one'\t at $line" unless $w_one eq $1;
    }
}
__PL__

open my $OUT1, '>', 'utf1' or die $!;
print {$OUT1} map chr hex, qw/61 61 c5 99 0a c4 8d 0a 61 61 c5 99 0a/;
close $OUT1;
open my $OUT2, '>', 'utf2' or die $!;
print {$OUT2} map chr hex, qw/c4 8d 0a 61 61 c5 99 0a c4 8d 0a/;
close $OUT2;

system "$^X utf2.pl < utf1";
print "\n";
system "$^X utf2.pl < utf2";

[download]
Does that help?

In reply to Re: Substring giving strange results on $1 with utf8 by Khen1950fx
in thread Substring giving strange results on $1 with utf8 by choroba

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