I'd suspect the servos!
I have found some digital servos do not work properly at 11ms on my DX-8's using an AR 8000.
Another problem can be caused by RX voltage dropout when the power source
cannot supply needed peak currents without a voltage sag.
(Had this problem with 4.8V NMIH RX packs and 2.5A 5V BEC's)
From the TX manual
The Frame rate function supports 22ms and 11ms. Default is
22ms. Change to 11ms when a 11ms Frame rate receiver is
used with compatible servos. The 11ms fast frame rate is not
compatible with some types of analog servos, so the 22ms rate
may be required.
Last edited by chuckk2; 04-07-2015 at 12:39 AM.