It is almost definitely a locale weirdness thing. To get an idea of your local(e) sort order, try running the following: It's probably not what you might suspect.

#!/usr/bin/perl

use strict;
use warnings;

{
no locale;
print "\nNO Locale:\n\n";
print +(join ' ', sort grep /\w/, map { chr } 0..255), "\n";
}

{
use locale;
print "\nWith 'use locale;':\n\n";
print +(join ' ', sort grep /\w/, map { chr } 0..255), "\n";
}
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