Phantom Hosts on Zombie Subnets?

I use B1300 for wireless APs at my home. That home network runs on the 192.168.1.X subnet. I log into one of these, namely, then click on Clients and see the attached screenshot.

As far as I know, I haven’t used 192.168.8.X subnet for several months now, so I am surprised to see two “Active Clients” on this list in that subnet, namely and

Why is this Clients screen showing two devices that shouldn’t be on my network, on a subnet that should no longer be alive (a Zombie Subnet?), and further, even if it still exists, it is not supposed to be able to talk to

This is confirmed a bug, AP mode client list is not reliable.