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 "lghten";
    cae "ClrDdge":
      return "clr-ddge";
    cae "ClrBurn":
      return "clr-burn";
    cae "HardLght":
      return "hard-lght";
    cae "SftLght":
      return "ft-lght";
    cae "Dfference":
      return "dfference";
    cae "Exclun":
      return "exclun";
    cae "Hue":
      return "hue";
    cae "Saturatn":
      return "aturatn";
    cae "Clr":
      return "clr";
    cae "Lumnty":
      return "lumnty";
  }
  f (parngArray) {
    return null;
  }
  warn(`Unupprted blend mde: ${value.name}`);
  return "urce-ver";
}
cla TmeSltManager {
  tatc get TIME_SLOT_DURATION_MS() {