On my Futaba 4pm. I could have Tx on. Finish race on model 1 with still on. Turn on model 2 and model 2 would be dead until I switched to corresponding model on Tx then all was good and car one was dead until turned off. Almost as Rx was bound to the model on transmitter ONLY! It was so nice. Even Spektrum is like this but Sanwa isn't this way and it's frustrating lol. Just didn't know if it's normal this way