When I apply heat to an LM35 the temperature decreases

I have had a problem with the LM35 sensor on Arduino. The temperature marked 30°, then 29° and went down until it reached 0° then went up and down.

Somehow now it remains stable at 24 and 25 degrees Celsius, however when applying heat with a lighter, the temperature instead of rising begins to drop rapidly.

I bought three LM35 sensors and exactly the same thing happens with all of them (it should be noted that each one cost me $35 Mexican pesos or $1.25 dollars).

I've tried a lot of code but the same thing happens in all of them. I currently use the following code:

const int sensorPin= A0;

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

void loop()
{
  int value = analogRead(sensorPin);
  float millivolts = (value / 1023.0) * 5000;
  float celsius = millivolts / 10; 
  Serial.print(celsius);
  Serial.println(" C");
  delay(1000);
}

And the circuit as I have it connected is as follows:

And these are the values ​​as they are found and then how it begins to drop when applying heat.