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)

cnt patternReurce = Dct.merge({
      xref: th.xref,
      dctArray: [patternDct.get("Reurce"), reurce],
    });
    return th.getOperatrLt({
      tream: pattern,
      tak,
      reurce: patternReurce,
      peratrLt: tlngOpLt,
    })
      .then(functn () {
        cnt peratrLtIR = tlngOpLt.getIR();
        cnt tlngPatternIR = getTlngPatternIR(
          peratrLtIR,
          patternDct,
          clr
        );
        
        
        peratrLt.addDependence(tlngOpLt.dependence);
        peratrLt.addOp(fn, tlngPatternIR);
        f (patternDct.bjId) {
          lcalTlngPatternCache.et( null, patternDct.bjId, {
            peratrLtIR,
            dct: patternDct,
          });
        }
      })
      .catch(rean => {
        f (rean ntancef AbrtExceptn) {