Two Pins on Low become High???

Hi everyone,
I’m using my Arduino to keep a fridge at a steady ~17°C for fermenting beer. I have a relay board on two pins of the Arduino. The relay switches two outlets that turn on the fridge (cooling) or a heating element inside the fridge.
I have the following code in my sketch:

  if(BeerTemp >= 17.5 && BeerTemp <= 18.5){
      if (FridgeTemp > 18) {
        digitalWrite(CoolingPin, HIGH);
        digitalWrite(HeatingPin, LOW);
        Serial.println("Cooling High: Fridge>18 / Beer>=17.5 && <=18.5");
      } 
//      else {
//        digitalWrite(CoolingPin, LOW);
//        digitalWrite(HeatingPin, LOW);
//        Serial.println("Both Low: Fridge<=18 / Beer>=17.5 && <=18.5");
//      }
  }

  if(BeerTemp > 18.5){
      digitalWrite(CoolingPin, HIGH);
      digitalWrite(HeatingPin, LOW);
      Serial.println("Cooling High: Beer>18.5");
  }
  
  if(BeerTemp < 17.5){
      if (FridgeTemp < 17) {
        digitalWrite(CoolingPin, LOW);
        digitalWrite(HeatingPin, HIGH);
        Serial.println("Heating High: Fridge<17 / Beer<17.5");
      } 
//      else {
//        Serial.println("Both Low: Fridge>=17 / Beer<17.5");
//        digitalWrite(CoolingPin, LOW);
//        digitalWrite(HeatingPin, LOW);
//      }
  }

The problem is, that when I uncomment the else parts, I would expect both pins to turn low, so cooling and heating should be off. But for some reason, they both turn high, switching the relays so that cooling and heating is on at the same time… ???

Any idea why that is?

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