Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Version 81.0.4044.138 (Official Build) (32-bit)
- Operating system and its version: Windows 10
- PDF.js version: latest
- Is a browser extension: no

Steps to reproduce the problem:

1. Open https://mozilla.github.io/pdf.js/web/viewer.html
2. Open the provided document
3. ctrl + F  and search for 'costs' .
4. Search for 'costs' - match NOT found.
5. Click the 'Download' and open the file in Adobe Reader, and search for costs - match is found.

What is the expected behavior? (add screenshot)
The word 'costs' to be returned by search

What went wrong? (add screenshot)
No results found

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):  https://mozilla.github.io/pdf.js/web/viewer.html
[2001_IESC_63_5_v6.pdf](https://github.com/mozilla/pdf.js/files/4644486/2001_IESC_63_5_v6.pdf)

return this._capability.promise;
  }
  /**
   * Cancel rendering of the textLayer.
   */
  cancel() {
    this._canceled = true;
    if (this._reader) {
      this._reader
        .cancel(new AbortException("TextLayer task cancelled."))
        .catch(() => {
          
        });
      this._reader = null;
    }
    if (this._renderTimer !== null) {
      clearTimeout(this._renderTimer);
      this._renderTimer = null;
    }
    this._capability.reject(new Error("TextLayer task cancelled."));
  }
  /**
   * @private
   */
  _processItems(items, styleCache) {