Tinkercad motor encoders stop working after stoping the motor and truning it back on

[dani_banc]

Hello,
I was trying to compute the speed of the motors in tinkercad and I observed that after I stop the motor, either by setting the pwm value to 0 or by writing LOW on both inputs of the motor, and then starting it again, the volatile variable inside my isr stops incrementing.

For the moment I am not computing the speed, but only printing the position variables:

#define IN1 8
#define IN2 7
#define IN3 11
#define IN4 12
#define ENA 10
#define ENB 9
#define ENCAL 2
#define ENCBL 4
#define ENCAR 3
#define ENCBR 5

// interrupt variables
volatile int pos_iL = 0;
volatile int pos_iR = 0;


void setup()
{
  Serial.begin(9600);

  // left motor setup
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(ENA, OUTPUT);

  // right motor setup
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  pinMode(ENB, OUTPUT);

  // encoder setup
  pinMode(ENCAL, INPUT_PULLUP);
  pinMode(ENCBL, INPUT_PULLUP);

  pinMode(ENCAR, INPUT_PULLUP);
  pinMode(ENCBR, INPUT_PULLUP);
  
  attachInterrupt(digitalPinToInterrupt(ENCAL), readEncoderLeft, RISING);
  attachInterrupt(digitalPinToInterrupt(ENCAR), readEncoderRight, RISING);
}

void loop()
{
  // periodically toggle the pwm between 0 and 100
  int pwm = (int)(100*(sin(micros()/1e6)>0));
  runMotors(pwm, 1, -1);
}

int runMotors(int speed, int dirLeft, int dirRight) {
  int posL = 0, posR = 0;
  noInterrupts();
  posL = pos_iL;
  posR = pos_iR;
  interrupts();
  Serial.print(posL);
  Serial.print(" ");
  Serial.println(posR);
  
  
  
  setMotor(IN1, IN2, ENA, speed, dirLeft);
  setMotor(IN3, IN4, ENB, speed, dirRight);
}

void setMotor(int in1, int in2, int en, int pwm, int dir) {
  analogWrite(en, pwm);
  if (dir == 1) {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
  } else if (dir == -1) {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
  } else {
    digitalWrite(in1, LOW);
    digitalWrite(in2, LOW);
  }
}

void readEncoderLeft() {
  int b = digitalRead(ENCBL);
  int increment = 0;
  if (b > 0) {
    increment = 1;
  }
  else {
    increment = -1;
  }
  pos_iL = pos_iL + increment;
}

void readEncoderRight() {
  int b = digitalRead(ENCBR);
  int increment = 0;
  if (b > 0) {
    increment = 1;
  }
  else {
    increment = -1;
  }
  pos_iR = pos_iR + increment;
}

The position variables increment until the motor stops, but when the motor starts again, they remain the same.

Here is the tinkercad design link:
https://www.tinkercad.com/things/eogJ4CCPVqh?sharecode=GVcSaNppgpvYntTKRMj66LSi94V9TuspmHKZ36gmFa4