Understood.
The problem has been discussed in the community before, and is not limited to just the Ecolink Contact Sensors, apparently. In my searches, I found reports of issues with many different Ecolink devices, and with other vendors.
Here's another community report on the Ecolink contact sensors: Ecolink Contact Sensor
Probably there's a parameter setting that will stop the devices sending 2 notifications.
TIA
