On my CX I've been there with the Tx batteries. My glitching stops when I have good Tx power, and it's sure to show up when the power is down.

My Falcon 40 gave me glitching fits for a while. I've been through a period of time when I was about to toss the helicopter - until one of my servos finally went away. With that servo replaced, the glitching stopped at that servo, the other servo stopped glitching and the overall power was stable again. Before that I would not have guessed that one servo could pull everything down. I was wrong. That one servo must have had a motor problem because it did pull the entire system down. Could be a servo pulling the voltage level of the system down and disconnecting the Rx momentarily.
Just a thought.

Soloboss