I'm thinking that your batteries are in need of being replaced. With a good RX battery you should be able to operate the system without flight loads for a couple of hours. The glitching could be caused by " dirty voltage " that the battery is providing especially if the internal resistance of the battery is high enough to intermittently short. Either way you are going to have to replace the batteries and there is a good chance it may fix the glitching issue. I personally stopped using 4.8V RX batteries 25 years ago and suggest 6V. That however with 72 MHz is just a personal preference but IMO a must with 2.4 ghz.