I would agree with Johnbuckner on this one.

Even very good pilots and careful builders can have an ocasional problem that looks like a radio interference problem.
If you look in my gallery you can see that I fly a broad range of airplanes. I am considered a better than average pilot even at 64 years of age. I test fly and instruct on a regular basis but in the last year I have flat spun one aircraft to the ground and put in a 35%extra of mine due to what looked like radio failure.
The aircraft that I spun in was from altitude in an upright spin that went flat to the point that it was unresponsive to any control movement and was witnessed by a fellow pilot standing beside me. It wasn't radio or mechanical but a cg situation coupled with a too small vertical fin and the ability of the wing to blank out the entire tailgroup in certain flight regimens.

The Extra showed normal voltage on all of the onboard voltage indicators two minutes before takeoff.
The takeoff was a normal rolling turn into 3 consecutive loops but the rudder started wagging to full deflection each way at the bottom of the third loop. I throttled back and came around in the pattern for an immediate landing only to have the airplane appear to go into failsafe as I was turning final. From there it made a wide circle and went down thru the edge of a tree.

Bottom line was that the servo battery which is independent of the receiver and runs thru a voltage regulator on a safety switch was discharged to the practically nothing.
How did this happen on a plane that had been flown for 6 years? I hooked it on a Minron charger that I had handy in the garage instead of the one that it normally uses in the hanger. The settings on the charger were wrong and I cycled the battery rather than charging it. Several things on my part could have prevented this but again it looked like a radio failure when it was a mistake strictly on my part.
My reputation is good enough that I could have claimed radio or mechanical problems and no one would have been the wiser. A lot of Goblins and Gremlins get blamed for radio problems while they in reality are busy finding other very creative ways to help the pilot reintroduce his airplane to the earth.