ESP32 Thing with a matrix keypad 4*4

Development Boards MicroMod
3

The code is simple, read key pressed and print on the terminal

On an Arduino Uno everything is ok, but when using on ESP32 thing I also get a special char on every loop.

#include <Arduino.h>
#include <Keypad.h>

// Keypad init
const byte ROWS = 4; 
const byte COLS = 4; 
char hexaKeys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {32, 33, 25, 26}; 
byte colPins[COLS] = {27, 14, 12, 13}; 
Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); 
char customKey;

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

// Loop
void loop()
{
  char customKey = customKeypad.getKey();
   Serial.println(customKey);
}
// Loop