I’m experiencing the same thing but with wireless and especially Apple TV. Same log message and the Apple TV report every 5-10 mins that it’s not connected to the network. This started after upgrading my AX88U to 386.2
I’ve experienced it before last year at one point with the previous tree firmware.... not sure of the exact firmware version though.
Apr 21 20:00:55 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:00 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:05 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:10 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:14 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:34 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:40 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:45 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Apr 21 20:01:50 kernel: C80:83:E0:63
3 not mesh client, can't update it's ip
Merlin stated these messages are debug messages that are internal to the Asus code so he can no disable them. He also stated they are not an indication of a problem.