Not being familiar with Hive, does your Hive device have the option of setting a static IP address on the device itself? If it does, I suggest trying giving it an IP address outside of the DHCP range of the hub and see if that resolves the problem.
Its not configurable by the user as far as I know. It connects to the HH6 by usb (for power) and ethernet. I'm going to keep a log of how often it loses connectivity and contact them when I have more data.
Thanks for the suggestion though.