Sorry I missed a part setting of VPN dnsmasq:
The updated full command is:
# set dnsmasq
uci set dhcp.@dnsmasq[0].local='/lan_chgd/'
uci commit dhcp
# restart dnsmasq
/etc/init.d/dnsmasq restart
# set VPN dnsmasq
sed -i 's/local=\/lan/local=\/lan_chgd/' /etc/dnsmasq.conf.vpn
# restart vpn dnsmasq
. /usr/bin/route_policy
handle_dns