bug ของ foreach กับตัวแปร $value

foreach ($options as $k => $v) {
   $sel = isset($value) && $value == $k ? ' selected' : '';
   $datas[] = '<option value="'.$k.'"'.$sel.'>'.$v.'</option>';
}

$value = isset($value) ? $value : $null;
foreach ($options as $k => $v) {
   $sel = $value == $k ? ' selected' : '';
   $datas[] = '<option value="'.$k.'"'.$sel.'>'.$v.'</option>';
}