I read . . . and I'm still trying to think of a scenario that would cause it.  Something in the ignition circut that pulls the receiver voltage below proper levels?  Should not happen if the module battery is isolated from the receiver battery.  Some bad circuitry in the module (we are assuming it is not a magneto ignition) that causes interference?  Is the kill-switch hardwired or optical?  Is the ignition battery cable near the receiver antenna?

Do you have an image of where the antenna wire is in the model?