As described on the mylyn-mantis user board, I face a problem regarding email notifications. It seems that some changes happening from the mylyn interface do not produce email notifications. The exact same changes made from the Mantis web interface generate the expected notifications so I don't think that it is related to any configuation on the serverside (nor any spam-reated problem). For instance, a "status" change does not fire any notification.

However, if you add a new comment to an issue from the mylyn interface, then a notification is corrrectly sent.

As pointed out on the mylyn mantis forum, it seems that the mylyn connector relies on the Mylyn SOAP api, so it would be the origin of the problem.