"is not of type String" when creating or editing group

When creating or editing a group I get this error:
is not of type String
This happens when the group name is longer then 31 chars.
In CRM/group/form/edit.php on line 349:
$name = CRM_Utils_String::titleToVar( $title );

titleToVar will return null causing CRM_Core_DAO::singleValueQuery to fail.

This also happened when importing contacts from a csv.

I also tried creating a group with a too long name on drupal.demo.civicrm.org and this works?

thx