Check your system log for any error related to dnsmasq. Asus did update dnsmasq on their end, they have a few manual commits that I didn't have, so it's possible they could have introduced a new issue specific to it.
I've checked the logs and am getting these two lines:
CRITICAL dnsmasq FAILED TO LOAD
CRITICAL illegal repeated keyword at line 50 of /etc/dnsmasq.conf
I've looked at dsnmasq.conf and it only has 49 lines - don't know what the illegal keyword is!
pid-file=/var/run/dnsmasq.pid
user=nobody
bind-dynamic
interface=br0
interface=pptp*
no-dhcp-interface=pptp*
no-resolv
servers-file=/tmp/resolv.dnsmasq
no-poll
no-negcache
cache-size=1500
min-port=4096
bogus-priv
domain-needed
dhcp-range=lan,192.168.72.2,192.168.72.254,255.255.255.0,43200s
dhcp-option=lan,3,192.168.72.1
dhcp-option=lan,252,"\n"
dhcp-authoritative
interface=tun21
interface=br1
dhcp-range=br1,192.168.101.2,192.168.101.254,255.255.255.0,86400s
dhcp-option=br1,3,192.168.101.1
interface=br2
dhcp-range=br2,192.168.102.2,192.168.102.254,255.255.255.0,86400s
dhcp-option=br2,3,192.168.102.1
interface=wgs1
no-dhcp-interface=wgs1
dhcp-host=00:11:32:F2:AB:CE,set:00:11:32:F2:AB:CE,192.168.72.6
dhcp-host=F8:E4:E3:F8:AF:B3,set:F8:E4:E3:F8:AF:B3,192.168.72.9
dhcp-option=tag:EC:C3:02:A0:1D:02,6,194.168.4.100,194.168.8.100
dhcp-host=EC:C3:02:A0:1D:02,set:EC:C3:02:A0:1D:02,Bedroom,192.168.72.252
dhcp-host=9C:AE:B3:BD:95:F9,set:9C:AE:B3:BD:95:F9,192.168.72.7
dhcp-host=14:59:C0:A0:EE:C5,set:14:59:C0:A0:EE:C5,192.168.72.2
dhcp-option=tag:E8:B2:FE:C9:49:26,6,194.168.4.100,194.168.8.100
dhcp-host=E8:B2:FE:C9:49:26,set:E8:B2:FE:C9:49:26,WiiRoom,192.168.72.253
dhcp-option=tag:E8:B2:FE:F9:1F:C2,6,194.168.4.100,194.168.8.100
dhcp-host=E8:B2:FE:F9:1F:C2,set:E8:B2:FE:F9:1F:C2,Livingroom,192.168.72.254
dhcp-host=B0:4E:26:34:CD:C0,set:B0:4E:26:34:CD:C0,192.168.72.4
dhcp-host=30:B1:B5:7A:61:78,set:30:B1:B5:7A:61:78,192.168.72.5
dhcp-host=00:21:04:F9:3D:F1,set:00:21:04:F9:3D:F1,192.168.72.3
dhcp-host=44:09:B8:98:A0:E7,set:44:09:B8:98:A0:E7,192.168.72.8
stop-dns-rebind
rebind-domain-ok=dns.msftncsi.com
dhcp-name-match=set:wpad-ignore,wpad
dhcp-ignore-names=tag:wpad-ignore
dhcp-script=/sbin/dhcpc_lease
script-arp
edns-packet-max=1232
dns-forward-max=1024