I think I have the same, or a related issue. Changing the Wifi Sync option did not help (it was off to begin with).
However completely disabling Wifi on the iPhone seems to solve the problem for me.
I got the same error messages with all the versions of UE4 I tried (4.7.6, 4.8.3, 4.9.0 P1). When Wifi on the iPhone is ON and the game has not been deployed to the device previously, I get these logs:
With Wifi OFF I am able to successfully deploy and play the game to the device.
Turning Wifi ON again, after a previous successful install will result in slightly different logs (the process seems to hang, instead of returning with an error):
Turning Wifi OFF again, will result in a successful install again.
I’m using an iPhone 5S with iOS 8.3 and I’ve been mainly experimenting with just the Blank BP template project.