I had a strange problem I have not seen in a long time
my iPhone 6+ with IOS 9 beta (problem did not occur with the asus beta builds) 5GHz
I have my media player by ethernet
I was having a very hard time controlling the media player with its IOS app, it kept losing sync with it, I tried to cycle wifi on my iPhone but the same problem after the phone goes to sleep for ~5 minutes or more.
I rebooted the router and the same problem.
Its weird as I did not notice this after a flash to this build.
Back to Asus beta builds
EDIT: I don't know what is going on, but latest Asus beta is the same, so I am going to separate the bands, and try 2.4 on asus beta and test from there. It could very well be IOS 9, I'll report this to apple.