Ecolink DWZWAVE2-ECO door/window sensor problem

I just got one of these Ecolink sensors. I can successfully add to ST, but the sensor reports open and never changes. I tried excluding (which works fine) and re-adding (which also works fine) a couple times, same result. When I pull the battery and re-insert, the red LED comes on for a few seconds and goes out, which indicates that it is getting a node ID from the ST hub. Once I change the state of the sensor with the magnet, the red LED comes back on solid and does not go back out. According the Ecolink’s troubleshooting guide, this means that it’s not getting a response back from the hub. Any ideas on things to try to fix this?

Well I guess it only works when the cover is off. Durrrr.