Does this happen many times in a row or just when you power on a machine that is attached wired to the router?
I ask this because I see this one time each day when I power on my machine or reboot it due to using NVidia Network Access Manager to team my two NIC's together. It's not a big deal and I know what is causing it on my end, if you are seeing it several times in a row then there may be some other issue.