Customer-suggested fix for this:

--- paste ---

From my perspective the "ignore-client-uids true;" should apply for the load-balancing decision as well, because in combination with failover the load balancing directly leads to a different IP for the same client (like if it were "false;").

Would it be OK to amend load_balance_mine() in server/failover.c

      oc = lookup_option(&dhcp_universe, packet->options,
                           DHO_DHCP_CLIENT_IDENTIFIER);
        memset(&ds, 0, sizeof ds);
        if (oc &&
            evaluate_option_cache(&ds, packet, NULL, NULL,
                                  packet->options, NULL,
                                  &global_scope, oc, MDL)) {
                hbaix = loadb_p_hash(ds.data, ds.len);

                data_string_forget(&ds, MDL);
        } else {
                hbaix = loadb_p_hash(packet->raw->chaddr,
                                     packet->raw->hlen);
        }

So that it also checks for the         
     oc = lookup_option(&server_universe, state->options,
                           SV_IGNORE_CLIENT_UIDS);
    ...
??? (have not checked if this state is available at this point...)

This SHOULD remove the problematic different load-balance decision when "ignore-client-uids true;"

--- /paste ---