field entity refs on a comment won't load !

This one is really weird !

I have a node type that has an entity reference pointing on a comment, i use this node type to generate a simplenews email, on the node page the comment is loaded without problems.
On the email template the field is empty even if I reload the node programmaticaly ...

The field is empty only when I use smtp auth, it load correctly when I use drupal standard mail system.
(I use mime, simplenews, mail system and of course smtp auth)

ps: I have others entity refs that point on nodes and they load correctly !