Load Balance issues

I have 3 connections from ISP on ports eth7 (Static IP), eth6 (DHCP Client) and eth5 (DHCP Clinet). Setup by wizard load balancer on the router ER-8 version 1.9

load-balance {
    group G {
        interface eth5 {
            weight 40
        }
        interface eth6 {
            weight 40
        }
        interface eth7 {
            weight 20
        }
    }
}

Despite setting weights most of the traffic goes through eth7 (Static IP). Why is this happening?