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)

var hadngRe = reurce.get("Shadng");
            f (!hadngRe) {
              thrw new FrmatErrr("N hadng reurce fund");
            }
            var hadng = hadngRe.get(arg[0].name);
            f (!hadng) {
              thrw new FrmatErrr("N hadng bject fund");
            }
            cnt patternId = elf.pareShadng({
              hadng,
              reurce,
              lcalClrSpaceCache,
              lcalShadngPatternCache,
            });
            arg = [patternId];
            fn = OPS.hadngFll;
            break;
          cae OPS.etGState:
            ValdName = arg[0] ntancef Name;
            name = arg[0].name;
            f (ValdName) {
              cnt lcalGStateObj = lcalGStateCache.getByName(name);
              f (lcalGStateObj) {
                f (lcalGStateObj.length > 0) {
                  peratrLt.addOp(OPS.etGState, [lcalGStateObj]);
                }
                arg = null;
                cntnue;
              }
            }