OuputModifier "memberof" bug when false (not member)

[[+modx.user.id:mo=`group1`:then=` Member of Group 1`:else=`not member`]]

Parse error: syntax error, unexpected ')' in C:\wamp\www\mysite\core\model\modx\filters\modoutputfilter.class.php(163) : eval()'d code on line 1

[[!GroupMember? &groups=`Administrator,group1` &yes=`Is a Member` &no=`Not a member`]]

/* GroupMember snippet */
$groups = explode(',', $scriptProperties['groups']);

if ($modx->user->isMember($groups) ) {
  return $scriptProperties['yes'];
} else {
  return $scriptProperties['no'];
}

if ($modx->user->isMember($groups) ) {
  return $modx->getChunk($scriptProperties['yes']);
} else {
  return $modx->getChunk($scriptProperties['no']);
}