dirtybird, we've had this discussion before. You are 100% right, on 2.4 GHz the interference can't be coming in through the RF port but it sure can come into the receiver on the battery and servo leads where it can cause all sorts of problems. In some cases, it can directly affect servo operation. The whole back end of the receiver / decoder / servos certainly operates with very low frequency signals that can easily be affected by spark noise. Our radios are systems and not just 2.4 GHz RF links. As Maxx has said, have seen it happen and is easily corrected when a loose cap is correctly installed. Likewise, on the old non shielded CH caps with separate ground wire .... let that ground wire get loose or break and watch what happens.