Emailnotification plugin

Hi, the email notification plugin seems to "forget" the subscriptions (achieved by ckliking the "subscibe" links that came with the plugin) on a tomcat restart unless each user goes to his user-page, uses "edit objects" and explicitly "saves" his subscriptions by clicking save objects. Did I configure anything wrongly or ist this normal behaviour? Is there a workaround? Thank you! Sascha Oesterle