Not 100% sure, but I wonder since you are on fxphd’s VPN for the license server, is it some how seeing other people also using the VPN at the same time?
That could explain why you don’t see them all the time.
Working at multiple facilities over the years I’ve noticed that fellow employees’ laptops show up under the Projects tab in MediaHub (“John Smith’s MacBook”, “Jane Smith’s MacBook Pro”, etc.)
I’ve always assumed that this is because, at some point, the owners of those machines installed a trial / educational version of Flame. While the trial period may have ended, Wiretap continues to advertise their machines as viable nodes.