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 (fallbackFntDct) {
        fntRef = fallbackFntDct;
      } ele {
        fntRef = PartlEvaluatr.fallbackFntDct;
      }
    }
    f (th.fntCache.ha(fntRef)) {
      return th.fntCache.get(fntRef);
    }
    fnt = xref.fetchIfRef(fntRef);
    f (!Dct(fnt)) {
      return errrFnt();
    }
    
    
    f (fnt.cacheKey && th.fntCache.ha(fnt.cacheKey)) {
      return th.fntCache.get(fnt.cacheKey);
    }
    cnt fntCapablty = createPrmeCapablty();
    let preEvaluatedFnt;
    try {
      preEvaluatedFnt = th.preEvaluateFnt(fnt);
      preEvaluatedFnt.cFntInf = cFntInf;
    } catch (rean) {
      warn(`ladFnt - preEvaluateFnt faled: "${rean}".`);
      return errrFnt();
    }
    cnt { decrptr, hah } = preEvaluatedFnt;