When uploading a pdf file, I get Warning: Unimplemented widget field type "null", falling back to base field type at pdf.worker.js. The file is not loading.
I'm using the chrome browser. All other files are processed fine, but this one is not. Help solve the problem.
[usn2020.pdf](https://github.com/mozilla/pdf.js/files/5936611/usn2020.pdf)

return this._hasFlag(this.flags, flag);
  }
  /**
   * Set the rectangle.
   *
   * @public
   * @memberof Annotation
   * @param {Array} rectangle - The rectangle array with exactly four entries
   */
  setRectangle(rectangle) {
    if (Array.isArray(rectangle) && rectangle.length === 4) {
      this.rectangle = Util.normalizeRect(rectangle);
    } else {
      this.rectangle = [0, 0, 0, 0];
    }
  }
  /**
   * Set the color and take care of color space conversion.
   * The default value is black, in RGB color space.
   *
   * @public
   * @memberof Annotation
   * @param {Array} color - The color array containing either 0
   *                        (transparent), 1 (grayscale), 3 (RGB) or
   *                        4 (CMYK) elements
   */
  setColor(color) {