Sonoff SNZB-04 stuck open

I just got this Sonoff Door/Windows sensor. it pairs in Smarthings as eWeLink. I can see the battery % = 100 (for a while it was stuck at 0% too), but the open/close state doesn’t change. I wondering now if I got a bad one, or hopefully I missed something in the setup.

a faint red light does come up in the device when opening/closing, but I see nothing in the IDE

It seems to be working now after deleting and pairing again. I’m not sure if that’s what did the trick. I also added a piece of paper between the battery and the plastic backing to make it fit more snuggly, since I suspect the device was going offline.