Use filesystem flag instead of NSDistributedNotification to signal that managedsoftwareupdate should stop. Turns out you can't send NSDistributedNotifications from user-land apps to background daemons launched by launchd.

code/client/managedsoftwareupdate

@@ -657,9 +657,6 @@ def main():
     if applesoftwareupdatesonly and options.verbose:
         print ('NOTE: managedsoftwareupdate is configured to process Apple '
                'Software Updates only.')
-    
-    # TESTING, TESTING
-    munkicommon.initNotificationDelegate()
 
     updatecheckresult = None
     if not options.installonly and not applesoftwareupdatesonly:
@@ -894,8 +891,6 @@ def main():
                             'SuppressUserNotification is true.')
 
     munkicommon.cleanUpTmpDir()
-    # TESTING TESTING
-    munkicommon.removeNotificationDelegate()
     if mustlogout:
         # not handling this currently
         pass