For reasons that are less than clear to me, my HH6 has been known to occasionally assign a static IP address to a device for no very obvious reason (it's not like it assigns static IP addresses to the another device of the same model from the same manufacturer, it happily gives *them* dynamic IP addreses).
I occasionally get brave and go to the router setup, find the device, and go and change it to a dhcp address.
Does it listen? Does it heck.
It's still itting there as a static IP address after that, even if the device isn't connected.