Re: Bug ? Sometime the dhcp IP is wrong for the client when I move a client from VLAN ID to another VLAN ID (using JDHCP)

Why don't you separate the dhcp-local-server interfaces into two groups, and explicitly specify the pool. Like this:

[system services]
dhcp-local-server {
	group VLAN14 {
		interface vlan.14;
		overrides {
			process-inform {
				pool LAN14-15;
			}
		}
	}
	group VLAN2 {
		interface vlan.2;
		overrides {
			process-inform {
				pool LAN2;
			}
		}
	}
}