Hello,
1- wich one ? the WXKG12LM ? if you can share the model id ? From my memory some of them haven’t the group cluster. And other need special magic at inclusion, but strange you have only the “off” and not the “on”. Can try to remove it and re-include it (there is some magic done during the inclusion)
2 - Perhaps somes hints here, same issue with ikea New IKEA TRÅDFRI LED bulbs turning themselves on
3- in Phoscon/help/API information you will be able to see software group and rules, but there is too hardware settings, that can be reset with reseting the device. But need first to remove the software part, because a watchdog can set it again.
To remove them, I think all is possible using phoscon, else direclty using the API.