Is this a new type of behavior, if I reset an Ikea plug for instance and which was previously joined and not deleted when you go into discovery it seems to do nothing, however the device is rejoined, when I do this on my older Hub it says its discovered a previous device. The only way to discover and this being mentioned is to remove the device.
I've seen this too. It will reconnect a device without notice popping up during discovery.
What firmware are you running? I'm on 22.214.171.124, but haven't seen this in a while
Running the same firmware, tried it on other zigbee devices and it does the same, if you delete the device then it tells you its discovered a new device but any existing devices don't get reported. The old hub is running 126.96.36.199