client-hostname not syncing between failover peers

[David Ehrmann]

I set up two servers to act as dhcp servers in a failover configuration. 
Everything works fine except for the missing client-hostname string in
dhcpd.leases.  The lease entry will show up on both servers, but
client-hostname is only on the server that handed out the lease.

Both report running version isc-dhcpd-V3.1.0, and the system clocks are
within a few seconds of each other.

Thanks in advance.