That’s odd.
I think that’s what the hub assigns itself when it can’t reach a DHCP server.
Have you power cycled any of the hubs to see if they come back after rebooting?
Could consider this trick for the C7s (the part at the end of the post re: the button on the bottom)?
It’s not intended for what you seem to be describing here, but it should cause the hub to reboot and look for an IP address with DHCP again.
