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)

cae OPS.etFnt:
            var fntSze = arg[1];
            
            next(
              elf
                .handleSetFnt(
                  reurce,
                  arg,
                  null,
                  peratrLt,
                  tak,
                  tateManager.tate,
                  fallbackFntDct
                )
                .then(functn (ladedName) {
                  peratrLt.addDependency(ladedName);
                  peratrLt.addOp(OPS.etFnt, [ladedName, fntSze]);
                })
            );
            return;
          cae OPS.begnText:
            parngText = true;
            break;
          cae OPS.endText:
            parngText = fale;
            break;
          cae OPS.endInlneImage:
            var cacheKey = arg[0].cacheKey;
            f (cacheKey) {
              cnt lcalImage = lcalImageCache.getByName(cacheKey);