Matrix Led (64x16) shows wrong

After along time exploering, I found when set intensity less than 0.3 , it would be ok.
it connect v3.3 . it' voltage may be a bit lower .
amazing...

demo code :

SPI2.setup({
  mosi: B15,
  sck: B13
});
var disp = require("MAX7219").connect(SPI2, B14, 16);

/** 呼吸灯效 */
function breath() {
  var light = 0.01;
  var increase = true;

  setInterval(function () {
    if (increase) {
      light += 0.01;
    } else {
      light -= 0.01;
    }

    if (light > 0.99) {
      increase = false;
    } else if (light < 0.01) {
      increase = true;
    }
    disp.intensity(light);
  }, 30);
}

var buffers = [
  // 开心家园
  [0, 0, 0, 0, 96, 2, 36, 0, 0, 0, 0, 0, 72, 2, 200, 33, 0, 14, 0, 0, 32, 2, 36, 8, 128, 0, 0, 0, 160, 1, 72, 41, 224, 15, 0, 0, 32, 2, 70, 16, 0, 28, 0, 30, 144, 7, 72, 40, 96, 2, 0, 0, 16, 2, 128, 63, 248, 49, 248, 48, 96, 121, 40, 46, 64, 2, 192, 0, 8, 2, 0, 30, 12, 0, 8, 34, 16, 49, 8, 32, 64, 50, 128, 49, 4, 2, 0, 0, 228, 3, 200, 33, 132, 1, 248, 63, 192, 63, 0, 33, 0, 2, 0, 0, 192, 4, 8, 38, 192, 1, 0, 0, 126, 2, 4, 0, 0, 0, 0, 0, 96, 4, 232, 33, 128, 0, 0, 0],
  // 照片可取
  // [0, 0, 0, 0, 60, 17, 32, 4, 0, 0, 0, 0, 240, 4, 88, 10, 0, 24, 0, 6, 36, 15, 224, 7, 0, 0, 0, 0, 16, 4, 72, 12, 52, 51, 32, 6, 0, 0, 48, 4, 192, 127, 192, 0, 0, 4, 200, 12, 108, 18, 32, 2, 36, 49, 16, 4, 30, 4, 252, 0, 0, 4, 120, 26, 108, 30, 32, 2, 68, 98, 8, 4, 0, 4, 72, 0, 0, 7, 71, 113, 124, 9, 32, 30, 2, 64, 0, 4, 248, 4, 72, 30, 0, 6, 64, 224, 228, 0, 224, 3, 0, 0, 0, 4, 144, 4, 88, 25, 0, 0, 96, 0, 100, 31, 32, 0, 0, 0, 0, 4, 144, 4, 72, 9, 0, 0, 0, 0],
  // 照片打印
  [0, 0, 0, 0, 252, 27, 32, 6, 0, 0, 0, 0, 32, 8, 0, 18, 0, 0, 0, 3, 56, 13, 224, 7, 32, 0, 0, 0, 56, 8, 104, 30, 0, 60, 0, 2, 0, 7, 48, 4, 32, 0, 192, 0, 38, 8, 28, 2, 124, 55, 48, 2, 36, 51, 16, 4, 32, 0, 32, 0, 32, 8, 12, 2, 104, 26, 32, 2, 100, 50, 24, 4, 32, 0, 24, 60, 32, 8, 0, 2, 104, 31, 32, 15, 6, 96, 12, 4, 224, 96, 12, 39, 48, 14, 0, 2, 248, 9, 224, 1, 0, 0, 0, 4, 60, 31, 104, 34, 0, 4, 0, 2, 232, 30, 32, 0, 0, 0, 0, 0, 96, 8, 24, 50, 0, 0, 0, 0],
  // 我还没睡
  [0, 0, 0, 0, 60, 26, 72, 48, 0, 0, 0, 0, 0, 15, 128, 63, 128, 1, 0, 0, 192, 8, 40, 2, 0, 0, 0, 0, 192, 4, 252, 2, 0, 1, 0, 0, 48, 4, 0, 2, 0, 4, 0, 12, 16, 5, 0, 122, 0, 13, 216, 63, 46, 14, 8, 2, 176, 7, 0, 6, 8, 2, 242, 7, 64, 1, 0, 2, 160, 9, 246, 0, 0, 5, 184, 3, 12, 7, 30, 2, 32, 1, 0, 3, 48, 112, 0, 255, 128, 4, 20, 30, 200, 24, 192, 31, 48, 15, 0, 3, 0, 96, 0, 0, 140, 60, 128, 19, 0, 112, 0, 0, 224, 1, 156, 24, 0, 0, 0, 0, 8, 0, 156, 18, 0, 0, 0, 0],
  // 可以取菜
  [0, 0, 0, 0, 208, 4, 216, 8, 0, 0, 0, 0, 120, 12, 128, 0, 0, 0, 0, 0, 48, 4, 120, 12, 0, 0, 32, 6, 200, 4, 252, 15, 0, 0, 0, 0, 0, 4, 24, 30, 0, 0, 96, 18, 120, 10, 224, 1, 240, 127, 0, 48, 0, 4, 24, 51, 252, 1, 252, 15, 78, 49, 176, 2, 12, 6, 128, 17, 0, 6, 136, 97, 72, 8, 0, 0, 64, 64, 152, 12, 0, 4, 24, 19, 0, 7, 192, 0, 72, 31, 128, 3, 64, 0, 132, 120, 248, 5, 24, 24, 0, 2, 0, 0, 88, 9, 96, 12, 0, 0, 192, 0, 144, 4, 152, 24, 0, 0, 0, 0, 72, 10, 144, 2, 0, 0, 0, 0]
].map(function (word) {
  return new Uint8Array(word).buffer;
});

var n = 0;

function getOne() {
  if (n >= buffers.length) {
    n = 0;
  }
  var b = buffers[n];
  n++;
  return b;
}

// var timer = null;
/** 开始闪耀 */
function blink() {

  // if (timer) {
  //   clearInterval(timer);
  // }
  // timer =
  setInterval(function () {
    disp.raw(getOne());
  }, 3000);

  breath();
}

blink();