I experienced a strange behavior this morning. My Dashboard showed a new device needing configuration. It turns out SmartThings thinks that I have added a new Centralite switch to my hub. I did not, and I only have one such switch, which is also still showing up on the device page. That one has been added months ago.
The device has a Device Network ID, different from the real switch, but no ZigBee ID.
Has anyone else seen new devices appear out of the blue?
I’ve seen this happeen when the hub loses some sort of connection with the original device. It’s only happened twice i think in two years. I don’t expect you’ll see it again.
Thanks for the reply. I need another switch and was hoping the elves dropped one off 
.
I’ve had a similar thing happen a handful of times. Basically what @tslagle13 was saying my hub loses connectivity with a device, then I readd it. However I actually like it in this instance because then I can move SmartApp’s from the old to the new without forgetting anything. Once each has been moved I exclude it.
Not the same thing because you didn’t initiate the new addition though.
The elves can drop me stuff anytime! Like currently I’d take 8 smart vents.
I went away for a week and when I returned SIX new “ghost” items appeared. Before this happened I noticed a device error out during Z-Wave repair. However, in the IDE, no such device existed. I suspect they are related but haven’t had time to diagnose it.
I deleted the items without any consequences.
I have also had this happen with a Centralite switch. Kinda frustrating imo.
When I got home, I confirmed that the ghost device controlled the same physical device as the real one. So I was able to turn the physical switch off using the ghost device tile and then turn the same physical switch back on with the original device tile. As @beckwith, I deleted the device, seemingly without consequence, at least so far.