I have a Ko Propo EX-1 UR that will not calibrate to my castle mmp esc. The weird thing is, I have the exact same set up in two cars. The radio calibrates with no issue to one car but not the other. Out of curiosity I tried a Traxxas radio/reciever and the problem esc calibrated to that radio with no issue. What would make that particular esc "not like" the KO radio? I am stumped.