I have MKS HBL380's all around except for throttle and choke which have HV1220's. I'm doing a transition from the 18SZ to the CORE radio. I pulled all of my Futaba Equipment from this airplane and installed PowerBox Receivers. The jerking happens on all servos. I've noticed that when the radio is turned off but the champion srs is turned on. the twitching/jerking disappears. The moment I turn the CORE radio on, the twitching begins immediately. Its very severe. Even though no functions are assigned in the Champion SRS, the twitching happens on all servos and moving the throttle stick up and down makes everything even worse. Keeping in mind I haven't even assigned anything to the throttle servo.