I have recently done a factory reset and it made no difference.

It is connected to LAN via gigabit switch.

I have tried in both router mode and AP mode.

The output of ifconfig is:

root@GL-AR750S:~# ifconfig
br-lan    Link encap:Ethernet  HWaddr E4:95:6E:45:92:48
          inet addr:192.168.8.1  Bcast:192.168.8.255  Mask:255.255.255.0
          inet6 addr: fe80::e695:6eff:fe45:9248/64 Scope:Link
          inet6 addr: fdf7:17ee:1a23:10::1/60 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2300659 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4619494 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6446985449 (6.0 GiB)  TX bytes:6196401678 (5.7 GiB)

    eth0      Link encap:Ethernet  HWaddr E4:95:6E:45:92:48
              inet6 addr: fe80::e695:6eff:fe45:9248/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:1876726 errors:0 dropped:0 overruns:0 frame:0
              TX packets:1128872 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:2288586757 (2.1 GiB)  TX bytes:965574794 (920.8 MiB)
              Interrupt:4

    eth0.1    Link encap:Ethernet  HWaddr E4:95:6E:45:92:48
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:11397 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:0 (0.0 B)  TX bytes:3662064 (3.4 MiB)

    eth0.2    Link encap:Ethernet  HWaddr E4:95:6E:45:92:48
              inet addr:192.168.0.222  Bcast:192.168.0.255  Mask:255.255.255.0
              inet6 addr: fe80::e695:6eff:fe45:9248/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:1870814 errors:0 dropped:2058 overruns:0 frame:0
              TX packets:1112169 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:2251140112 (2.0 GiB)  TX bytes:956355249 (912.0 MiB)

    lo        Link encap:Local Loopback
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:65536  Metric:1
              RX packets:475 errors:0 dropped:0 overruns:0 frame:0
              TX packets:475 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1
              RX bytes:51316 (50.1 KiB)  TX bytes:51316 (50.1 KiB)

    wlan0     Link encap:Ethernet  HWaddr E4:95:6E:45:92:49
              inet6 addr: fe80::e695:6eff:fe45:9249/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:6119729 errors:0 dropped:0 overruns:0 frame:0
              TX packets:4629220 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:6685424853 (6.2 GiB)  TX bytes:6292474797 (5.8 GiB)