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;
      }
      f (th.ptn.gnreErrr) {
        
        warn(
          `getTextCntent - gnrng errr durng "${tak.name}" ` 
            `tak: "${rean}".`
        );
        fluhTextCntentItem();
        enqueueChunk();
        return;
      }
      thrw rean;
    });
  }
  extractDataStructure(dct, t, prperte) {
    cnt xref = th.xref;
    let cdTGdByte;
    
    cnt tUncdePrme = th.readTUncde(
      prperte.tUncde || dct.get("TUncde") || t.get("TUncde")