I agree with Harry !
Set the modulation to auto and see if that changes anything
I run all my planes with weatronic and 14MZ, every model is set to "PPM12" in the transmitter, do NOT attempt to use PCM, you will get a small "jitter" every 60 seconds, that is when the transmitter sends out the failsafe configuration to the (Futaba) receiver, Weatronic has warned us of NOT using PCM on that one ! (I don't know if this has changed in the latest FW versions, but I doubt)!