Strange device name in client list

[sfx2000]

Indeed. Unless other people start reporting similar strange names appearing by themselves I guess we'll never know. I suspect it was just a one-off caused by "000925" contained within a corrupted nvram variable.

well - because the IEEE OUI assignments are based on the honor system - there's no regulatory enforcement here...

It only takes a couple of keystrokes for a factory in Shenzen to program a MAC address header into the factory line, and build stuff... I usually see things like this on cheap Android TV boxes and IP cameras from China - not calling them out directly, just stating what is...

going back to OP's concerns - it could be a fake switch, or it could be someone re-wrote the MAC addr of the switch itself, this is possible.