RE: CC BEC causing interference or damaged?
definitely sounds like the bec is causing the interference if the problem goes away when you remove it from the system. I have found that BECs can easily cause glitches, even on spektrum systems. Check your placement of the BEC. Going to be tough on such a small heli but you probably have it sitting to close to something else. I can tell you that you don't want it anywhere near your rx or gyro if you can as I have had the most troubles when they are close.
See if you cant unmount the bec but leave it connected and stretch it out away from the rest of the electronics while the heli is powered up and glitching. If the problem goes away and the bec is powering the rx up fine, I'd bet there is no problem with it and it is just too close to something else.