For anyone else monitoring this, I also disabled my ISY V3 skill in Alexa, deleted the routine, then re-enabled the V3 skill, and tested to make sure that it sees state changes on sensor ( it does, very consistently, ) and then I recreated the very simple routine to send notification upon closure of sensor. It still doesn't work. Based on garybixler's post, I did attempt to cycle the sensor many times, to see if it ever worked, but I have yet to get a single trigger of the routine.
I've reviewed a ton of entries in the various Alexa forums, and their developers site, but haven't found anything that gives me any hint or corrective action.