NullpointerException in Roster class

Seeing this in the error logs of Openfire 3.9.3:

It’s from this line appearently:

https://github.com/igniterealtime/Openfire/blob/v3.9.3/src/java/org/jivesoftware /openfire/roster/Roster.java#L128

Any ideas, how this happens? rosterManager seems to be null here.

2015.09.18 13:28:44 org.jivesoftware.openfire.handler.PresenceUpdateHandler - Interner Serverfehler. Triggered by packet:

0

java.lang.NullPointerException
at org.jivesoftware.openfire.roster.Roster.(Roster.java:128)
at org.jivesoftware.openfire.roster.RosterManager.getRoster(RosterManager.java:116 )
at org.jivesoftware.openfire.handler.PresenceUpdateHandler.broadcastUpdate(Presenc eUpdateHandler.java:307)
at org.jivesoftware.openfire.handler.PresenceUpdateHandler.process(PresenceUpdateH andler.java:149)
at org.jivesoftware.openfire.handler.PresenceUpdateHandler.process(PresenceUpdateH andler.java:137)
at org.jivesoftware.openfire.handler.PresenceUpdateHandler.process(PresenceUpdateH andler.java:201)
at org.jivesoftware.openfire.PresenceRouter.handle(PresenceRouter.java:148)
at org.jivesoftware.openfire.PresenceRouter.route(PresenceRouter.java:84)
at org.jivesoftware.openfire.spi.PacketRouterImpl.route(PacketRouterImpl.java:84)
at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:12 0)
at org.jivesoftware.openfire.SessionPacketRouter.route(SessionPacketRouter.java:75 )
at org.jivesoftware.openfire.http.HttpSession.sendPendingPackets(HttpSession.java: 645)
at org.jivesoftware.openfire.http.HttpSessionManager$HttpPacketSender.run(HttpSess ionManager.java:425)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)