We now know it's a USB keyboard.
Code:
uhidev0 at uhub3 port 5 configuration 1 interface 0
uhidev0: vendor 0x04d9 USB Keyboard, rev 1.10/3.10, addr 3, iclass 3/1
ukbd0 at uhidev0
wskbd0 at ukbd0: console keyboard, using wsdisplay0
I don't see any USB related kernel errors reported, but I do see detachment and attachment of a Kingston DataTraveler USB stick. Do you have keyboard problems if the stick is never connected?