It is the radio... I can think of at least 4 guys i race with who have had this same issue.. basically you can send it in to get looked at or do what they did.. they changed to a new UnUsed model on the radio and started all the settings over.. i seen 2 that had to go to a third channel.. it should work till you run out of channels LOL..
the guys ive seen this happen to either lost all or some right or left hand steering..