Some new issues.
I am experiencing 5Ghz wifi Degradation on performance. I am going from 70-90Mbps down to like 3-5. This is using 339 firmware. Also another side effect is the connection is not consistent, it will like "Hang" then go on as normal then "hang" while doing something like browsing/speed test.
My roommate says he's experienced that as well a few times since I set up our AC68R recently. Did you find a solution by chance or any additional info about this?