It does add multiple time the same object, changing slighlty the MAC address.
For example, my wife Iphone MAC address is: 30:F7:xx:xx:DB:8F, it then adds another entry with 02:0F:xx:xx:DB:8F
basically changing 30:F7 with 02:0F.
It does this also to my samsung.
Are you using icloud also? You will get one entry for the icloud device tracker and one for the netgear tracker. However, the icloud entry shouldn’t have a mac address.
Also is 192.168.1.247 the IP address of your router?
I would use one or the other, there is really no reason to use both. I have found nmap to be very consistent and had trouble with netgear. This may be why you have multiple entries, nmap is giving the second entry as it names them by mac address and netgear will pull a name like your first entry.
The errors aren’t harmful, so you can leave it there if you want. I removed it just so I didn’t have to sort through those errors while looking for other stuff while testing.
Just understand that removing it won’t allow automatic discovery of components. Those components are documented here: