L7 router given by TMNut has bugs in their crappy firmware. Seems like another D-Link judging from the web interface. My sis home is using one. It use channel 4 even when I set it to channel 11. Upon surveying the neighbouring wifi network, all the other wifi network with @unifi name is at channel 4. Guess they also using the crappy L7 router with defective firmware.

I strongly suggest you to change the wireless router to something else.

Mikrotik is nice & very stable, but it's OpenVPN implementation is useless but most people don't need it.
DD-WRT on newer router overloaded with unnecessary functions & codes, too unstable in my experience irregardless what chipset the router is using. Not much better than stock firmware in term of stability for certain routers.
Tomato firmware is much better than DD-WRT, stable enough to not requiring any reboots for weeks if it works well for your router. Broadcom chipset only.
OpenWRT is good if you like to toy & experimenting. Quite stable for certain routers, but don't expect it to work as expected or stable if your router is just newly supported.

Generally I would recommend Asus or Linksys with Broadcom chipset & gigabit lan if you want to use Tomato router on Unifi. Non gigabit Broadcom switch chip cannot handle VLAN 500 & 600 at the same time. Atheros chipset no problem, but if the stock firmware is unstable, you may have to resort to Open-WRT or DD-WRT.

If you don't want to use third party firmware, TP-Link with dual band wifi maybe a good alternative as it is relatively cheap. I only used the old WR1043ND before, though not exactly as stable as I wanted it to be, it is still much better than all my crap D-Links.