// 23 August 2023
// Forum: https://forum.arduino.cc/t/digitalwrite-writes-wrong-pins/1161120
// Bug ? Pin 10 and 5 start flashing.

void setup() 
{
  pinMode(5, OUTPUT);
  pinMode(A6, OUTPUT);    // not allowed, it is analog input only
  pinMode(A7, OUTPUT);    // not allowed, it is analog input only

  digitalWrite(5, HIGH);
}

void loop() 
{
  digitalWrite(A6, !digitalRead(A6));  // not allowed, it is not a digital pin
  digitalWrite(A7, !digitalRead(A7));  // not allowed, it is not a digital pin
  delay(500);
}