nrf24l01 + old aritronics + L298N need a little help.

Something about this code has me puzzled. Can you shed some light on this bit of code and what it does in my program.

void loop() {

LMotor = joystick[0];
RMotor = joystick[2];

If I leave it out entirely, Right motor works but acceleration is in wrong direction. I pushup and motor smoothly accelerates. If I push down it starts at full speed then slows down as joystick travels further from center. In this case reversing my map from low to high does not make a difference. Left Motor does nothing.

With the bit of code as it is written above in the sketch. The right motor works exactly as expected. Left does nothing.

if I change at piece to what I think it should be:

void loop() {

LMotor = analogRead (joystick[0]);
RMotor = analogRead (joystick[2]);

Then I'm back to right motor behaving exactly as with first example where I leave out that piece entirely and my serial monitor not displaying joystick inputs.