Hmm if you have the failsafe. it should had gone to CT at the first hint of interference or a low batt situation.Maybe your paranoia with the truck driver might be real.He could have his radio on his truck scanning channels on 27 , 40 and 72 . Which could confuse your rc receiver.. maybe i'm not sure.The radio sends out signals and your reciever picks it up which maybe the failsafe didn't kick in.. Maybe somebody with a radio scanner can try this test if failsafe screws up when someone is doing this?

Caus since you were not alone there having the problem it has to be intereference in that sector.Did you saw any signs of glitching... even minimal ones not just the MJ ones? while at idle?