From my limited understanding of this and digging through the source code it looks like the reason that the presence is not being restored is because the plugin believes that there is always still a call active.
If I make more than one call the debug log shows 3 call sessions at the end of the second call and 1 call session at the end of the first call.
Not sure if this helps anyone with the problem.
2007.03.23 12:25:18 Asterisk-IM: Processing NewState:UP event channel : IAX2/IAX-voip1-1 id: 1174652716.36
2007.03.23 12:25:18 Asterisk-IM OnPhoneTask: Could not find device/jid mapping for device IAX2/IAX-voip1 returning
2007.03.23 12:25:18 Asterisk-IM: Processing NewState:UP event channel : SIP/9758-b79084b8 id: 1174652716.35
2007.03.23 12:25:18 Asterisk-IM OnPhoneTask called for user PhoneUser{id=4, username=’‘thompsonm’’}
2007.03.23 12:25:18 Set special presence for thompsonm:
2007.03.23 12:25:51 Asterisk-IM HangupTask not active IAX2/IAX-voip1
2007.03.23 12:25:51 Asterisk-IM HangupTask called for user PhoneUser{id=4, username=’‘thompsonm’’}
2007.03.23 12:25:51 Asterisk-IM HangupTask: User thompsonm has 3 call sessions, not restoring presence. Destroying CallSession{id=1174652728.37, channel=SIP/9758-b7903530}
2007.03.23 12:25:51 Asterisk-IM HangupTask: Remaining CallSession CallSession{id=’‘1174652716.36’’, channel=’‘SIP/9758’’, linkedChannel=’‘null’’, callerID=’‘9758’’, forwardedExtension=’‘null’’, forwardedJID=null, dialedJID=null, username=’‘thompsonm’’, isMonitored=false}
2007.03.23 12:25:51 Asterisk-IM HangupTask: Remaining CallSession CallSession{id=’‘1174652716.35’’, channel=’‘SIP/9758’’, linkedChannel=’‘null’’, callerID=’‘9758’’, forwardedExtension=’‘null’’, forwardedJID=null, dialedJID=null, username=’‘thompsonm’’, isMonitored=false}
2007.03.23 12:26:02 Asterisk-IM HangupTask not active IAX2/IAX-voip1
2007.03.23 12:26:02 Asterisk-IM HangupTask called for user PhoneUser{id=4, username=’‘thompsonm’’}
2007.03.23 12:26:02 Asterisk-IM HangupTask: User thompsonm has 1 call sessions, not restoring presence. Destroying CallSession{id=1174652716.35, channel=SIP/9758-b79084b8}
2007.03.23 12:26:02 Restoring special presence for thompsonm
2007.03.23 12:26:02 Restoring special presence for thompsonm