Почему объекты класса не имеют рандомного перемещения по X

class Butterfly {
  constructor(srcButterfly) {
    const calcTraectory = () => {
      this.widthWindow = window.innerWidth;
      this.heightWindow = window.innerHeight;
      const randomWidth = getRandomInt(50, 200);
      const randomX = getRandomInt(0, this.widthWindow - randomWidth);
      const randomY = getRandomInt(0, this.heightWindow - randomWidth);
      this.x = randomX;
      this.y = randomY;
      this.lastX = this.x;
      this.width = randomWidth;
      this.srcButterfly = srcButterfly;
    }
    window.addEventListener('resize', calcTraectory);
    calcTraectory();
    this.draw();
  }

  randomGenerator(time) {
    const randomWidth = getRandomInt(50, 200);
    const randomX = getRandomInt(0, this.widthWindow - randomWidth);
    const randomY = getRandomInt(0, this.heightWindow - randomWidth);
    this.x = randomX;
    this.y = randomY;
    this.width = randomWidth;
  }

  draw() {
    const butterflyHtml = document.createElement('img');
    butterflyHtml.src = this.srcButterfly;
    this.node = butterflyHtml;
    this.node.style.position = 'absolute';
    this.node.style.width = this.width + 'px';
    this.node.style.left = this.x + 'px';
    this.node.style.top = this.y + 'px';
    body.prepend(this.node);
  }

  moveUp() {
    this.y--;
    this.node.style.left = this.x + 'px';
    this.node.style.top = this.y + 'px';
  }

  moveRight() {
    this.x++;
    this.node.style.left = this.x + 'px';
  }

  moveLeft() {
    this.x--;
    this.node.style.left = this.x + 'px';
  }

  moveRandomLeftOrRight() {
    let f = this.moveRandomLeftOrRight_ || (this.moveRandomLeftOrRight_ = {});

    if (!f.callCount) f.callCount = 0;
    if (!f.maxCount) f.maxCount = getRandomInt(50, 150);
    if ((this.widthWindow - this.x - this.width > f.maxCount) && this.x > f.maxCount && !f.direction) {
      f.direction = getRandomInt(0, 1) ? 'Right' : 'Left';
    } else if (this.widthWindow - this.x - this.width > f.maxCount && !f.direction) {
      f.direction = "Right";
    } else if (this.x > f.maxCount && !f.direction) {
      f.direction = "Left";
    }


    if (++f.callCount >= f.maxCount) {
      f.maxCount = getRandomInt(50, 150);
      if ((this.widthWindow - this.x - this.width) > f.maxCount && this.x > f.maxCount) {
        // Если налево и направо есть место, то случайно можно пойти налево и направо
        f.direction = getRandomInt(0, 1) ? 'Right' : 'Left';
      } else if (this.widthWindow - this.x - this.width > f.maxCount) {
        // Иначе если есть место идти направо, то направо
        f.direction = "Right";
      } else if (this.x > f.maxCount) {
        // Иначе если есть место идти налево, то налево
        f.direction = "Left";
      }
      f.callCount = null;
    }

    this["move" + f.direction]();
  }

  move(fpsTime = 60) {
    let fps, fpsInterval, startTime, now, then, elapsed;
    const startAnimate = (fps = 60) => {
      fpsInterval = 1000 / fps;
      then = Date.now();
      startTime = then;
      animate();
    }
    const animate = () => {
      let myReq = reqAnimFrame(animate);
      now = Date.now();
      elapsed = now - then;
      if (elapsed > fpsInterval) {
        then = now - (elapsed % fpsInterval);
        drawAnimate();
      }
    };
    const drawAnimate = () => {
      if (this.y + this.node.scrollHeight < 0) {
        this.randomGenerator(fpsTime);
      }
      this.moveRandomLeftOrRight();
      this.moveUp();
    }
    startAnimate(fpsTime);
  }
}

function getRandomInt(min, max) {
  const rand = min + Math.random() * (max + 1 - min);
  return Math.floor(rand);
}

const reqAnimFrame = (function() {
  return requestAnimationFrame ||
    mozRequestAnimationFrame ||
    webkitRequestAnimationFrame ||
    oRequestAnimationFrame ||
    msRequestAnimationFrame ||
    function(callback) {
      setTimeout(callback, 1000 / 60);
    }
})();

const srcBlueButterfly = "https://aidanwalshblog.files.wordpress.com/2018/02/butterfly_blue.gif";
const srcBrownButterfly = "https://s8.hostingkartinok.com/uploads/images/2019/08/f55cda56fa8caa3f141c43f79af058d1.gif";

const body = document.querySelector('body');

const brown = new Butterfly(srcBrownButterfly);
brown.move(60);
const brown1 = new Butterfly(srcBrownButterfly);
brown1.move(60);
const brown2 = new Butterfly(srcBrownButterfly);
brown2.move(60);
const blue = new Butterfly(srcBlueButterfly);
blue.move(60);
const blue1 = new Butterfly(srcBlueButterfly);
blue1.move(60);
const blue2 = new Butterfly(srcBlueButterfly);
blue2.move(60);