Contact names from additional language forms not "saved"

I've got bilingual (en_US/fr_CA) forms for donation, membership and event on a site and they all work perfectly in the default language (en_US). They work almost perfectly in the additional language except that the first names and last names are not "saved" properly. What i mean is that the names don't show up in a listing and the contacts created use the email address as the "name". The first and last names entered on the forms are actually saved as they are present in the correct fields when you edit the contact. To make them show up you just have to "edit" and then "save" the contact.

I've reproduced this on the Drupal CiviCRM demo

en_US form http://drupal.demo.civicrm.org/civicrm/contribute/transact?reset=1&id=1&lcMessages=en_US
fr_CA form http://drupal.demo.civicrm.org/civicrm/contribute/transact?reset=1&id=1&lcMessages=fr_CA

It is the same for all the forms with different profiles used for each and doesn't seem to have anything to do with the use of a Drupal language prefix eg. /fr/civicrm ... or a CiviCRM language suffix (I use the &lcMessages=en_US on the forms too)

This search on the demo shows the first contact without name which was entered from the fr_CA version of the above form. You will find the first and last names are in the edit screen of the contact filling out the fr_CA version of the form. First try showed the same with just an email address second included the Supporter profile. Both contacts show with no name.

http://drupal.demo.civicrm.org/civicrm/contact/search&reset=1
search for neil