Bluetooth communication "stopping" after some time

Hello,

I have two Arduino Mega connected with bluetooth modules, two LED and two strain gauges (used as weight sensors), all of these connected like on the attached images (don’t mind the third bluetooth module on the images). I wanted each LED to be powered on when appliying a certain weight on the sensor connected to the same Arduino and powered off when the two sensors are activated, so I wrote these two codes :
For the right Arduino :

const int Sensor = 0;
void setup() 
{
  Serial1.begin(9600);
  Serial.begin(9600);
  pinMode(2, OUTPUT);
  digitalWrite(2, LOW);
}

void loop() 
{
  float AnalogValue = analogRead(Sensor);
  float Volt = (AnalogValue)/204.6;
  
   if(Volt<4.4) //If there is no weight on the right sensor
  {
  Serial1.write('A');
  digitalWrite(2, LOW);
  }
  if (Volt>=4.4) //If there is weight on the right sensor
  {
    Serial1.write('C');
    if (Serial1.read()=='B') //If there is no weight on the left sensor
    {
      digitalWrite(2, HIGH);
    }
    else        //If there is weight on the left sensor
    {
      digitalWrite(2, LOW);
    }
  }
}

For the left Arduino :

const int Sensor = 0;
void setup() 
{
  Serial1.begin(9600);
  Serial.begin(9600);
  pinMode(2, OUTPUT);
  digitalWrite(2, LOW);
}

void loop() 
{
  float AnalogValue = analogRead(Sensor);
  float Volt = (AnalogValue)/204.6;
  //Ecriture
  if(Volt<4.4) //If there is no weight on the left sensor
  {
  Serial1.write('B');
  digitalWrite(2, LOW);
  }
  if (Volt>=4.4) //If there is weight on the left sensor
  {
    Serial1.write('D');
    if (Serial1.read()=='A') //If there is no weight on the right sensor
    {
      digitalWrite(2, HIGH);
    }
     else          //If there is weight on the right sensor
     {
      digitalWrite(2, LOW);
     }
  }
}

At first, this works very good and there is no problem, but after 2 minutes there is no response, I think the bluetooth modules are flooded with information and cannot do anything, but I really don’t know how to fix this problem…

Thanks in advance,
Peter