Is solved my problem with a quick workaround :)

use strict;

$|=1;

use CGI;

my $q = new CGI;

my %in = map { $_ => $q->param($_) } $q->param;

print $q->header;
foreach my $key (keys %in) {
    print $key.$in{$key};
}
[download]

But I still don't know why it works when giving a sample input straight into and scalar. And when slurping the the file in a scalar it doesn't work anymore and behaves different?

--
My opinions may have changed,
but not the fact that I am right