Activity detecting all keyboard events except for backspace inside the EditText

Question

I'm currently trying to implement a framework to capture every user interaction with the application. I have an Activity that can capture the user key events as the following:

@Override
public boolean dispatchKeyEvent(@NonNull KeyEvent kEvent) {
    final int action = kEvent.getAction();
    final int keyCode = kEvent.getKeyCode();
    final char character = (char) kEvent.getUnicodeChar();
    if (action == KeyEvent.ACTION_UP) {
        Log.i(">>>>DEBUG", "KEY EVENT");
        final long res = kEvent.getEventTime() - this.timestampLastKeyboardEvent;
        switch (keyCode) {
            case KeyEvent.KEYCODE_DEL:
                // FIXME
                this.capuccinoEventLogger.removeLastCharacter();
                break;
            case KeyEvent.KEYCODE_TAB:
            case KeyEvent.KEYCODE_ENTER:
                this.capuccinoEventLogger.markLastCapuccinoEventFinal();
                break;
            default:
                // HACK: there is a strange behaviour when a special character is
                // typed the current method is invoked twice, one for the normal
                // key and the other for the shift + key code.
                if (res != 0) {
                    CapuccinoKeyboardEvent ce = new CapuccinoKeyboardEvent(character);
                    this.capuccinoEventLogger.addNewCapuccinoEvent(ce);
                }
                break;
        }
        this.timestampLastKeyboardEvent = kEvent.getEventTime();
    }
    return super.dispatchKeyEvent(kEvent);
}

The problem is, every key is being detected except for the backspace, when I'm trying to capture events from an EditText. Why this is happening?