Alerts and recall on Programs (ODF) don't work

Here is stack trace when sending an alert on a program:
2016-03-24 09:31:43,808 ERROR [org.ametys.cms.alerts.AlertEngine] (AlertEngine;/plugins/core/servercomm/messages.xml) An error occurred sending the alerts.
java.lang.NullPointerException
at org.ametys.web.rights.PageRightsContextConvertor.getContentFromContext(PageRightsContextConvertor.java:135)
at org.ametys.plugins.newsletter.right.NewsletterRightsContextConvertor.convertContext(NewsletterRightsContextConvertor.java:37)
at org.ametys.web.rights.WebHierarchicalProfileBasedRightsManager.getAliasContext(WebHierarchicalProfileBasedRightsManager.java:143)
at org.ametys.web.rights.WebHierarchicalProfileBasedRightsManager.getGrantedUsers(WebHierarchicalProfileBasedRightsManager.java:58)
at org.ametys.cms.alerts.AlertEngine._sendInstantAlertEmail(AlertEngine.java:374)
at org.ametys.web.alerts.AlertEngine._sendInstantAlertEmail(AlertEngine.java:156)
at org.ametys.cms.alerts.AlertEngine._sendInstantAlerts(AlertEngine.java:357)
at org.ametys.cms.alerts.AlertEngine._sendAlerts(AlertEngine.java:334)
at org.ametys.web.alerts.AlertEngine._sendAlerts(AlertEngine.java:103)
at org.ametys.cms.alerts.AlertEngine.run(AlertEngine.java:283)
at java.lang.Thread.run(Thread.java:745)