My spouse noticed recently that my home made cat feeder door was closing on Simone while she was eating when it should have stayed open, and has for 5 years or so. She has been wearing the same RFID tag the whole time and we can hear her walking around when it clatters against her name tag on her collar. I compared the tag with another one just like it and it seemed to have the same range, but I changed them out on her collar and now the door doesn't close while she is eating, so I have to assume the old tag was not functioning as well as the new one. So I am a little confused. Any ideas on this?