DHCP Failover restart service config file mismatch

[#1]

Hello guys, 

I post here because I have a little problem, and I need advices.

Currently, I have a DHCP failover with a primary and a secudary in the default restart group.

Sometimes when I restart DHCP service, I see in the logs this message : 

failover peer Infrabel-DHCP-FO(1645715775p): I move from normal to communications-interrupted

Failover CONNECT from Infrabel-DHCP-FO : Dhcpd config file mismatched, please restart your dhcpd service.

I receive also a mail alert to DHCP Service in warning state

The default restart group contains only these two machines and is configured to restart sequentially.

Is it better to restart simultanously ?

Is there some parameter to change like the Maximum Number of Unacked Updates ?

Have a nice day,