It is a known problem and maybe it will be fixed in future firmware.

If more users request for modification on this "design problem", maybe it will be improvd in future. :)

Confirm with TP-LINK people to see if it will be improved in future firmware. Share it here for others to refer to. :) http://www.tp-link.com/en/Support/contact/

Did you report it to TP-LINK support? http://www.tp-link.com/en/Support/contact/ Share it here pls if you get a reply.

There is a new hardware version for W8970 now. Hard to say if there is newer firmware to release and fix this issue. You may confirm TP-LINK people directly. http://www.tp-link.com/en/Support/contact/

Yours is D7 as well? Did you contact TP-LINK support team before you replace it? You'd better feed it back to them directly. http://www.tp-link.com/en/Support/contact/.