DHCPv6 Server DUID Being Rejected By Clients

[sirwobbythefirst]

I have DHCPv6 setup and enabled on two OPNsense routers and every so often I get an issue where a client will refuse to pull an IPv6 address from one server because it is expecting the Server DUID of another server. Where do I go to change this Server DUID so that both servers match?

And for the inevitable question, one router is set to be disconnected by default, and is only connected once SHTF and the main router goes down. The two are identical, barring the MAC address of a third network adapter which is used for administration and the hostname and in this instance, the Server DUID used by DHCPv6.