It's very rare. 

You can contact tplink tec support to get some advice.

Hmm. I wonder if it's somehow related to an issue I had with my RE450 bridge. I have 2 gigabit LAN networks bridged using an RE450 in the livingroom (WiFi extension disbled, only bridge mode) and a TP-Link Archer C1200 in the office where the internet is.

When I have my DirecTV DVR LAN port connected to a switch (tried two different switches) going through the RE450 to the internet side, my bridge fell apart and was unstable. Using a computer on either end pinging two different destinations on the other end would result in random 200-300ms delays. Sometimes a delay would only happen to one destination and not the other pinging from the same computer, while other times it would be flipped or the delay would be split between each destination.

I haven't run any packet captures yet, but I really want to soon to see WHY the DirecTV box is killing my bridge. When I pull the cable out of DirecTV, my pings go to 1 to 3. But after 4 seconds of plugging in the network cable to DirecTV, the bridge is unstable and packets are being held somewhere and delayed. And the DirecTV box wasn't even using any bandwidth, the switch LEDs hardly blinked.

I don't know yet if it's being caused by the RE450 or the router on the other end. I'll need to reprogram my old ASUS RT-N12 WiFi router in bridge mode to replace my new RE450 and see if I still see delayed packets.

I have since fixed the issue by using the DirecTV's WiFi to connect directly to my router's WiFi. But if I can figure out what those packets are that DirecTV is sending out, maybe this could be an exploited vulnerability all these extenders or routers have.

EDIT: Just tested it, even though I have my DirecTV DVR set to use my WiFi for its connectivity, when I plug in the ethernet cable into my bridge I lose pings instantly again. Strange, even though the LAN is not used on the DirecTV, it still kill my bridge.

EDIT2 (12/22/18): Pulled my RE450 bridge and installed my old ASUS RT-N12 w/Tomato firmware in client bridge mode. Basically the same configuration. Plugging in the DirecTV DVR had the same affect, but maybe about 40% lower. The pings still had a delayed affect and had random timing affects on the pings. So maybe the router has the problem. But, knowing the shlt firmware of the (AT&T now owned) DirecTV GUI, I could say the DirecTV receiver is flooding the network. But more tests need to be done.