This is due to latest dev on email gateway:

Notice: Undefined index: name in /mnt/plugins/tracker/include/Tracker/Artifact/Tracker_Artifact_Changeset.class.php on line 873
Call Stack
#    Time    Memory    Function    Location
1    0.0002    684520    {main}( )    ../index.php:0
2    0.0703    24185424    TrackerManager->process( object(HTTPRequest)[41], object(PFUser)[42] )    ../index.php:33
3    0.0704    24185680    TrackerManager->processSubElement( object(Tracker)[61], object(HTTPRequest)[41], object(PFUser)[42] )    ../TrackerManager.class.php:124
4    0.0983    27139504    Tracker->process( object(TrackerManager)[58], object(HTTPRequest)[41], object(PFUser)[42] )    ../TrackerManager.class.php:107
5    0.1139    30274472    Tracker_Action_CopyArtifact->process( object(TrackerManager)[58], object(HTTPRequest)[41], object(PFUser)[42] )    ../Tracker.class.php:725
6    0.1473    40457232    Tracker_Action_CopyArtifact->processCopy( object(Tracker_Artifact_Changeset)[175], object(PFUser)[42], array(6) )    ../CopyArtifact.class.php:120
7    0.1719    42687344    Tracker_Artifact_XMLImport->importOneArtifactFromXML( object(Tracker)[61], object(SimpleXMLElement)[176], string(0), object(TrackerXmlFieldsMapping_InSamePlatform)[174] )    ../CopyArtifact.class.php:158
8    0.1853    44328040    Tracker_Artifact_XMLImport->importOneArtifact( object(Tracker)[61], object(SimpleXMLElement)[176], object(Tracker_Artifact_XMLImport_ArtifactFieldsDataBuilder)[180] )    ../XMLImport.class.php:142
9    0.1854    44328800    Tracker_Artifact_XMLImport->importInitialChangeset( object(Tracker)[61], object(SimpleXMLElement)[270], object(Tracker_Artifact_XMLImport_ArtifactFieldsDataBuilder)[180] )    ../XMLImport.class.php:164
10    0.1863    44341704    Tracker_ArtifactCreator->create( object(Tracker)[61], array(4), object(PFUser)[42], long, bool )    ../XMLImport.class.php:197
11    0.2990    47480824    Tracker_Artifact_Changeset->notify( )    ../Tracker_ArtifactCreator.class.php:88
12    0.3785    50479216    Tracker_Artifact_Changeset->sendNotification( array(1), array(1), string(18), string(17181), string(9122), null )    ../Tracker_Artifact_Changeset.class.php:683