Intermittent DNS resolution issue

I already answered these points in post nº 5. There's no IPv6 anywhere in sight on my WAN or LAN.

The current output to

ubus call system board; \
uci export network; \
uci export dhcp; uci export firewall; \
ip -4 addr ; ip -4 ro li tab all ; ip -4 ru; \
ip -6 addr ; ip -6 ro li tab all ; ip -6 ru; \
ls -l  /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/* ; head -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/*

is :

{
	"kernel": "5.10.161",
	"hostname": "ArcherA6",
	"system": "Qualcomm Atheros QCA956X ver 1 rev 0",
	"model": "TP-Link Archer C6 v2 (US) / A6 v2 (US/TW)",
	"board_name": "tplink,archer-c6-v2-us",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "22.03.3",
		"revision": "r20028-43d71ad93e",
		"target": "ath79/generic",
		"description": "OpenWrt 22.03.3 r20028-43d71ad93e"
	}
}
package network

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'fdeb:10f9:9e35::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0.1'
	option ipv6 '0'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.1.1'

config interface 'wan'
	option device 'eth0.2'
	option proto 'dhcp'
	option peerdns '0'
	list dns '9.9.9.9'
	list dns '149.112.112.112'
	option hostname '*'

config interface 'wan6'
	option device 'eth0.2'
	option proto 'dhcpv6'

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch0'
	option vlan '1'
	option ports '2 3 4 5 0t'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '1 0t'

config device
	option name 'wlan0'
	option ipv6 '0'

config device
	option name 'wlan1'
	option ipv6 '0'

config device
	option name 'eth0'
	option ipv6 '0'

package dhcp

config dnsmasq
	option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option expandhosts '1'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option localservice '1'
	option ednspacket_max '1232'
	option local '/local/'
	option domain 'local'
	option logqueries '1'

config dhcp 'lan'
	option interface 'lan'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	option start '2'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config odhcpd 'odhcpd'
	option maindhcp '0'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option loglevel '4'

config host
	option name 'MiWiFi'
	option dns '1'
	option mac '50:D2:F5:XX:YY:ZZ’
	option ip '192.168.1.4'

config host
	option name 'fvdw'
	option dns '1'
	option mac '00:D0:4B:XX:YY:ZZ'
	option ip '192.168.1.10'

config host
	option name 'Lancelot-Mo'
	option dns '1'
	option mac 'A8:20:66:XX:YY:ZZ'
	option ip '192.168.1.20'

config host
	option name 'Whitebook'
	option dns '1'
	option mac '00:26:B0:XX:YY:ZZ'
	option ip '192.168.1.21'

config host
	option name 'Canon-MFP'
	option dns '1'
	option mac 'F4:81:39:XX:YY:ZZ'
	option ip '192.168.1.24'

config host
	option name 'Think-PC'
	option dns '1'
	option mac '50:7B:9D:XX:YY:ZZ'
	option ip '192.168.1.25'

config host
	option name 'LibreELEC'
	option dns '1'
	option mac 'B8:27:EB:XX:YY:ZZ'
	option ip '192.168.1.26'

config host
	option name 'Lancelot-wifi'
	option dns '1'
	option mac '5C:96:9D:XX:YY:ZZ'
	option ip '192.168.1.50'

config host
	option name 'Whitebook-wifi'
	option dns '1'
	option mac '00:26:08:XX:YY:ZZ'
	option ip '192.168.1.51'

config host
	option name 'Oboo-clock-7176'
	option dns '1'
	option mac '40:A3:6B:XX:YY:ZZ'
	option ip '192.168.1.59'

config host
	option name 'MiniPad'
	option dns '1'
	option mac '68:9C:70:XX:YY:ZZ'
	option ip '192.168.1.60'

config host
	option name 'CubyPad'
	option dns '1'
	option mac '84:29:99:XX:YY:ZZ'
	option ip '192.168.1.61'

config host
	option name 'Z6252CA'
	option mac '92:15:C8:XX:YY:ZZ'
	option ip '192.168.1.66'

config host
	option name ‘Joe-PC'
	option dns '1'
	option mac '68:CA:00:01:47:DF'
	option ip '192.168.1.68'

config host
	option mac 'F4:B1:9C:XX:YY:ZZ'
	option name 'Geeni-cam'
	option dns '1'
	option ip '192.168.1.70'

config host
	option name 'Omega-F079'
	option ip '192.168.1.150'
	option mac '40:A3:6B:XX:YY:ZZ'

config host
	option name 'wdnas'
	option dns '1'
	option mac '00:00:C0:XX:YY:ZZ'
	option ip '192.168.1.213'

config domain
	option name 'fvdwsl-base.local'
	option ip '192.168.1.10'

config host
	option name 'Think-Air'
	option ip '192.168.1.53'
	option mac 'A4:D1:8C:XX:YY:ZZ'

config host
	option name 'Joe2'
	option dns '1'
	option mac '90:DE:80:XX:YY:ZZ'
	option ip '192.168.1.67'

package firewall

config defaults
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option synflood_protect '1'

config zone
	option name 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'
	list network 'lan'

config zone
	option name 'wan'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option masq '1'
	option mtu_fix '1'
	list device 'tun0'
	list network 'wan'
	list network 'wan6'

config forwarding
	option src 'lan'
	option dest 'wan'

config rule
	option name 'Allow-DHCP-Renew'
	option src 'wan'
	option proto 'udp'
	option dest_port '68'
	option target 'ACCEPT'
	option family 'ipv4'

config rule
	option name 'Allow-Ping'
	option src 'wan'
	option proto 'icmp'
	option icmp_type 'echo-request'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-IGMP'
	option src 'wan'
	option proto 'igmp'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-DHCPv6'
	option src 'wan'
	option proto 'udp'
	option dest_port '546'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-MLD'
	option src 'wan'
	option proto 'icmp'
	option src_ip 'fe80::/10'
	list icmp_type '130/0'
	list icmp_type '131/0'
	list icmp_type '132/0'
	list icmp_type '143/0'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Input'
	option src 'wan'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	list icmp_type 'router-solicitation'
	list icmp_type 'neighbour-solicitation'
	list icmp_type 'router-advertisement'
	list icmp_type 'neighbour-advertisement'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Forward'
	option src 'wan'
	option dest '*'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-IPSec-ESP'
	option src 'wan'
	option dest 'lan'
	option proto 'esp'
	option target 'ACCEPT'

config rule
	option name 'Allow-ISAKMP'
	option src 'wan'
	option dest 'lan'
	option dest_port '500'
	option proto 'udp'
	option target 'ACCEPT'

config rule
	option name 'Support-UDP-Traceroute'
	option src 'wan'
	option dest_port '33434:33689'
	option proto 'udp'
	option family 'ipv4'
	option target 'REJECT'
	option enabled 'false'

config include
	option path '/etc/firewall.user'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option src 'wan'
	option src_dport '4222-4228'
	option name 'fvdwsl-base1'
	option dest_ip '192.168.1.10'
	option dest_port '4222-4228'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option src 'wan'
	option src_dport '4215-4221'
	option name 'Syno1'
	option dest_ip '192.168.1.15'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option name 'Syno2'
	list proto 'tcp'
	option src 'wan'
	option src_dport '51418-51419'
	option dest_ip '192.168.1.15'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option src 'wan'
	option src_dport '9091-9093'
	option name 'fvdwsl-base2'
	option dest_ip '192.168.1.10'
	option dest_port '9091-9093'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option name 'Syno3'
	option src 'wan'
	option src_dport '5006'
	option dest_ip '192.168.1.15'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option name 'Syno4'
	option src 'wan'
	option src_dport '3001'
	option dest_ip '192.168.1.15'
	option enabled '0'

config forwarding
	option dest 'lan'

config forwarding
	option dest 'lan'

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
6: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    inet 192.168.1.1/24 brd 192.168.1.255 scope global br-lan
       valid_lft forever preferred_lft forever
8: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    inet 38.xxx.yyy.180/28 brd 38.xxx.yyy.191 scope global eth0.2
       valid_lft forever preferred_lft forever
default via 38.xxx.yyy.177 dev eth0.2 proto static src 38.xxx.yyy.180 
38.xxx.yyy.176/28 dev eth0.2 proto kernel scope link src 38.xxx.yyy.180 
192.168.1.0/24 dev br-lan proto kernel scope link src 192.168.1.1 
broadcast 38.xxx.yyy.176 dev eth0.2 table local proto kernel scope link src 38.xxx.yyy.180 
local 38.xxx.yyy.180 dev eth0.2 table local proto kernel scope host src 38.xxx.yyy.180 
broadcast 38.xxx.yyy.191 dev eth0.2 table local proto kernel scope link src 38.xxx.yyy.180 
broadcast 127.0.0.0 dev lo table local proto kernel scope link src 127.0.0.1 
local 127.0.0.0/8 dev lo table local proto kernel scope host src 127.0.0.1 
local 127.0.0.1 dev lo table local proto kernel scope host src 127.0.0.1 
broadcast 127.255.255.255 dev lo table local proto kernel scope link src 127.0.0.1 
broadcast 192.168.1.0 dev br-lan table local proto kernel scope link src 192.168.1.1 
local 192.168.1.1 dev br-lan table local proto kernel scope host src 192.168.1.1 
broadcast 192.168.1.255 dev br-lan table local proto kernel scope link src 192.168.1.1 
0:	from all lookup local
32766:	from all lookup main
32767:	from all lookup default
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
8: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 fe80::6aff:7bff:fe03:8555/64 scope link 
       valid_lft forever preferred_lft forever
unreachable fdeb:10f9:9e35::/48 dev lo proto static metric 2147483647 pref medium
fe80::/64 dev eth0.2 proto kernel metric 256 pref medium
local ::1 dev lo table local proto kernel metric 0 pref medium
anycast fe80:: dev eth0.2 table local proto kernel metric 0 pref medium
local fe80::6aff:7bff:fe03:8555 dev eth0.2 table local proto kernel metric 0 pref medium
multicast ff00::/8 dev eth0.2 table local proto kernel metric 256 pref medium
0:	from all lookup local
32766:	from all lookup main
lrwxrwxrwx    1 root     root            16 Jan  2 19:24 /etc/resolv.conf -> /tmp/resolv.conf
-rw-r--r--    1 root     root            49 Apr 26 12:42 /tmp/resolv.conf
-rw-r--r--    1 root     root            62 Apr 26 12:42 /tmp/resolv.conf.d/resolv.conf.auto

/tmp/resolv.conf.d:
-rw-r--r--    1 root     root            62 Apr 26 12:42 resolv.conf.auto
==> /etc/resolv.conf <==
search local
nameserver 127.0.0.1
nameserver ::1

==> /tmp/resolv.conf <==
search local
nameserver 127.0.0.1
nameserver ::1

==> /tmp/resolv.conf.d <==
head: /tmp/resolv.conf.d: I/O error

==> /tmp/resolv.conf.d/resolv.conf.auto <==
# Interface wan
nameserver 9.9.9.9
nameserver 149.112.112.112

These aren't the droids I'm looking for.

As of now I'm trying to find out a suitable display filter for Wireshark before the problem reoccurs.