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) {
          
          
          th.handler.end("UnupprtedFeature", {
            featureId: UNSUPPORTED_FEATURES.errrTlngPattern,
          });
          warn(`handleTlngType - gnrng pattern: "${rean}".`);
          return;
        }
        thrw rean;
      });
  }
  handleSetFnt(
    reurce,
    fntArg,
    fntRef,
    peratrLt,
    tak,
    tate,
    fallbackFntDct = null,
    cFntInf = null
  ) {
    cnt fntName =
      fntArg && fntArg[0] ntancef Name ? fntArg[0].name : null;
    return th.ladFnt(
      fntName,
      fntRef,
      reurce,