Calendar Block always shows first of the month as the first square in the calendar (ie, the 1st is always Sunday)

Hi all,

For some reason, in my installation, the Calendar Block always shows the first of the month as the first day in the first week (for instance, for September 2009, the first is a Sunday, same for October 2009).

Is this something that should be set in my module's hook_calendar_block, or is this a bug?

my implementation of hook_calendar_block:

function sas_events_calendar_block(&$calendar, &$date, $op) {
  switch($op) {
    case 'alter':
      $date->content = l($date->day, 'sas_events/'.$date->year.'-'.$date->month.'-'.$date->day);
      break;
  }
}

Thanks!