Fields on privatemsg do not show until cache clear

I believe the attached patch is the correct solution, but maybe there's another way?

If you have this problem and just need a workaround instead of a patch, you can implement this in a custom module:

function MODULE_NAME_field_attach_insert($entity_type, $entity) {
  if ($entity_type == 'privatemsg_message') {
    cache_clear_all("field:privatemsg_message:{$entity->mid}", 'cache_field');
  }
}