Default New update and 5Ghz WiFi radio

I have two fire TVs which I updated to the new firmware yesterday. One of the units cannot see my 5Ghz network after update.
I did factory reset and no change. Then I pushed the previous firmware and the problem solved. Updating again breaks the 5Ghz network. I think there is a new radio on the updated firmware that making the problem.

the strange thing is my other updated unit connects fine to the 5Ghz router.