I exported the event handler JSON to make some changes and after importing the changes I was thrown a couple of these errors.
Event handler 'EH_964391': Event type must have a 'detectorXID'
The exported JSON shows "detectorXID":null
It even shows me the e-mail lists and it says it is not disabled.
The GUI, however, doesn't show that I have any e-mail set up for the even that would trigger it.