macOS에서 Linux VIP 접속시 하나만 붙는 현상

#!/usr/bin/env bash

interface=$1
event=$2

if [ -z "${interface}" ]; then
    exit
fi

vip="192.168.1.36/24"
wlan="wlan0"
eth="enp4s0f3u1u4"

date "+%Y-%m-%d %H:%M:%S" >> /tmp/if.log
echo "INTERFACE : ${interface}" >> /tmp/if.log
echo "EVENT : ${event}" >> /tmp/if.log

if [ "${interface}" = "${wlan}" ]; then
    if [ "${event}" = "up" ]; then
        if [ -z "$(ip addr  | grep "${eth}")" ]; then
            vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
            if [ ! -z "${vip_dev}" -a "${vip_dev}" != "${wlan}" ]; then
                ip addr delete ${vip} dev ${vip_dev}
                ip addr add ${vip} dev ${wlan}
            fi
            vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
            if [ -z "${vip_dev}" ]; then
                ip addr add ${vip} dev ${wlan}
            fi
        fi
    fi
elif [ "${interface}" = "${eth}" ]; then
       if [ "${event}" = "up" ]; then
        vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
        if [ ! -z "${vip_dev}" -a "${vip_dev}" != "${eth}" ]; then
            ip addr delete ${vip} dev ${vip_dev}
            ip addr add ${vip} dev ${eth}
        fi
        vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
        if [ -z "${vip_dev}" ]; then
            ip addr add ${vip} dev ${eth}
        fi
    elif [ "${event}" = "down" ]; then
        vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
        if [ ! -z "${vip_dev}" -a "${vip_dev}" != "${wlan}" ]; then
            ip addr delete ${vip} dev ${vip_dev}
            ip addr add ${vip} dev ${wlan}
        fi
        vip_dev="$(ip addr | grep "${vip}" | sed -e 's/^.* //g')"
        if [ -z "${vip_dev}" ]; then
            ip addr add ${vip} dev ${wlan}
        fi
    fi
fi