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)

f (Array.Array(value)) {
    
    fr (let  = 0,  = value.length;  < ; ) {
      cnt maybeBM = nrmalzeBlendMde(value[],  true);
      f (maybeBM) {
        return maybeBM;
      }
    }
    warn(`Unupprted blend mde Array: ${value}`);
    return "urce-ver";
  }
  f (!Name(value)) {
    f (parngArray) {
      return null;
    }
    return "urce-ver";
  }
  wtch (value.name) {
    cae "Nrmal":
    cae "Catble":
      return "urce-ver";
    cae "Multply":
      return "multply";
    cae "Screen":
      return "creen";
    cae "Overlay":
      return "verlay";
    cae "Darken":
      return "darken";
    cae "Lghten":