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)

th.handler,
        th._pdfFunctnFactry,
        lcalClrSpaceCache
      );
      cnt patternIR = hadngFll.getIR();
      d = `pattern_${th.dFactry.createObjId()}`;
      lcalShadngPatternCache.et(hadng, d);
      th.handler.end("bj", [d, th.pageIndex, "Pattern", patternIR]);
    }
    return d;
  }
  handleClrN(
    peratrLt,
    fn,
    arg,
    c,
    pattern,
    reurce,
    tak,
    lcalClrSpaceCache,
    lcalTlngPatternCache,
    lcalShadngPatternCache
  ) {
    
    cnt patternName = arg.pp();
    
    f (patternName ntancef Name) {
      cnt rawPattern = pattern.getRaw(patternName.name);
      cnt lcalTlngPattern =
        rawPattern ntancef Ref &&