Internet Load Balancer Bidirectional High Memory Issue

I have a BIGIP 4200 serves as Internet Load Balancer Bidirectional. When the BIGIP connected to 2 Internet Service Provider (for uplink), memory increased. The Memory of BIGIP was normal if only 1 ISP was connected.

Fyi,

ltm rule /Common/iRule_geolocation {
    when CLIENT_ACCEPTED {
if {[whereis [IP::local_addr] country] equals "ID"} {
        pool pool_def_gw_iix
} else {
        pool pool_def_gw
}
}
}

ltm rule /Common/iRule_select_snatpool {
    when CLIENT_ACCEPTED {
if {[class match [IP::client_addr] equals dg_snat_2]} {
        snatpool snat_overload
        return
        } 
if { [class match [IP::client_addr] equals dg_snat_4]} {
        snatpool snat_4
        return
        }
if { [class match [IP::client_addr] equals dg_snat_5]} {
        snatpool snat_SAP_Proxy
        return
        }
if { [class match [IP::client_addr] equals dg_snat_7]} {
        snatpool snat_7
        return
        }
if { [class match [IP::client_addr] equals dg_snat_8]} {
        snatpool snat_8
        return
        }
else {
reject
}
}
}

ltm snatpool /Common/snat_4 {
    members {
        /Common/180.x.x.2
        /Common/202.x.x.2
    }
}
ltm snatpool /Common/snat_7 {
    members {
        /Common/180.x.x.3
        /Common/202.x.x.3
    }
}
ltm snatpool /Common/snat_8 {
    members {
        /Common/180.x.x.4
        /Common/202.x.x.4
    }
}
ltm snatpool /Common/snat_SAP_Proxy {
    members {
        /Common/180.x.x.5
        /Common/202.x.x.5
    }
}
ltm snatpool /Common/snat_overload {
    members {
        /Common/180.x.x.2
        /Common/202.x.x.6
    }
}

Regards