You might try soldering a relatively large (1000uF or so) cap onto the battery connectors of the ESC. This often helps reduce glitching due to noise generated by the ESC's large, switching, output currents. Guys that run electric RC cars do this to reduce glitching and give them more "punch" when they accelerate. Another option would be to solder a cap across the power supply wires coming from the ESC to the RX. This would filter the RX's power supply, and hopefully reduce the glitching as well. Also, your motor should have some caps or Shottky diodes on its terminals to keep inductive kick-back from the motor coils to a minimum. This also reduces sparking of the motor brushes, and makes them last longer...