Arduino Zero digitalRead in output mode

Official Hardware Classic Zero
1

Hi

On an Arduino UNO I can read the pin state set with digitalWrite value using readRead but on an an Zero board. The following code works on an UNO/Leonardo but not on an Zero

void setup() {
  // initialize digital pin 13 as an output.
  pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(13, !digitalRead(13) );   // turn the LED on/off
  delay(1000);              // wait for a second
}

Is there a other way to read the current pin state?