Vor void setup()
Code:
volatile int ISR_Uebergabe = 0;
Ohne static funktionierts einwandfrei - Zufall?
Code:
void loop() {
  digitalWrite(LEDgnPin, 1);
  digitalWrite(LEDrtPin, 0);
  __TP__(1);
  ISR_Uebergabe = 1;
  Pausen_ms(3000);
  
  digitalWrite(LEDgnPin, 0);
  digitalWrite(LEDrtPin, 1);
  __TP__(2);
  ISR_Uebergabe = 2;
  Pausen_ms(3000);

  digitalWrite(LEDgnPin, 1);
  digitalWrite(LEDrtPin, 1);
  __TP__(3);
  ISR_Uebergabe = 3;
  Pausen_ms(3000);
}