Yep, it's locale. I'm getting different results, depending on TZ value. But changing TZ after I've called UnixDate once doesn't have any effect.

#!/usr/bin/perl 

use strict;
use warnings;
use Date::Manip;
use Data::Dumper;

my $tot_start_date = '2008-06-27 17:37:11 +0000';
my $tot_end_date = '2008-09-29 04:02:18 +0000';
my $beta_start_date = '2008-09-29 04:02:18 +0000';
my $beta_end_date = '2009-01-07 00:00:00 -0800';
    
#$ENV{TZ}='America/Montreal';
$ENV{TZ}='UTC';

$tot_start_date = UnixDate($tot_start_date,"%Y-%m-%d");
$tot_end_date   = UnixDate($tot_end_date,"%Y-%m-%d");
$beta_start_date = UnixDate($beta_start_date,"%Y-%m-%d");
$beta_end_date   = UnixDate($beta_end_date,"%Y-%m-%d");

print Dumper $tot_start_date;
print Dumper $tot_end_date;
print Dumper $beta_start_date;
print Dumper $beta_end_date;

__END__

output for Montreal:

$VAR1 = '2008-06-27';
$VAR1 = '2008-09-28';
$VAR1 = '2008-09-28';
$VAR1 = '2009-01-07';

output for UTC:

$VAR1 = '2008-06-27';
$VAR1 = '2008-09-29';
$VAR1 = '2008-09-29';
$VAR1 = '2009-01-07';
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