I2C problem: communication between Arduino Mega and Motorcontroller

Good evening!

I would like to communicate between an Arduino Mega and a Wild Thumper Motorcontroller. The Arduino Mega is the slave and writes two values (L and R) between 0 and 255 to the Motorcontroller, which is the slave.

The problem is that only one side (L or R) gets the expected value. When I looked into the serial monitor, only the left side had the value 101, the right side had 0. Please, could anyone help me?

Arduino Mega code (slave):

void setup()
{
  Wire.begin(1);
  Wire.onRequest(I2Cmode);
}

void loop()
{
  
}

void I2Cmode()
{ 
  L=100;
  R=101;
    
  Wire.write(L);
  delay(5);
  Wire.write(R);
  delay(5);
}

Motorcontroller code (master):

void I2Cmode()
{ 
    Wire.requestFrom(1, 1);                                    // 2^8bit => 1byte
    
    
    while(Wire.available())
    {
      LR = Wire.read();
    }
    
    if(LR %2 == 0)                                              // LR = even number
    {
      L=LR;
    }
    else if(LR %2 ==1)                                          // LR = uneven number
    {
      R=LR;
    }

    
  
    
    Serial.print(LR);
    Serial.print("\n");
    Serial.print(L);
    Serial.print("\n");
    Serial.print(R);
    Serial.print("\n\n");

    
    Leftmode=0;                                                 // both sides go forward
    Rightmode=2;
    
    LeftPWM=abs(L);                
    LeftPWM=min(LeftPWM,255);                                   // set maximum limit 255

    RightPWM=abs(R);             
    RightPWM=min(RightPWM,255);                                 // set maximum limit 255
    
}