DHCP server not work on new interface

For Developers
1

I use 18.06.1 version OpenWRT, Once I change interface name from br-lan to new interface name(also a bridge interface) at uci-defaults folder, DHCP server not working when booting the system. After check, it's return at below function in etc/init.d/dnsmasq

    # If there's no carrier yet, skip this interface.
    # The init script will be called again once the link is up
    case "$(devstatus "$ifname" | jsonfilter -e @.carrier)" in
            false) return 1;;
    esac

According the notes, it should re-run dnsmasq script when the carrier change to true. Even I hot-plug the internet, it's not be execute again.
But if I issue "/etc/init.d/network restart", the problem is gone, The dnsmasq script will be execute again when I hot-plug the internet.
The issue happened when I change the interface name, is there need additional settings to enable hot-plug feature when I use new bridge interface?

12/28 update.....
It seems bridge interface issue, I bridge eth4, eth0 then connect eth0, the dhcp client can not get IP when booting. But bridge eth0,eth4 connect eth0, the dhcp client can get IP.
How to fix the problem? or any setting need to config?

Thanks.