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)

wdthBuf.puh(entry.tStrng());
          }
        }
        hah.update(wdthBuf.jn());
      }
      f (cte) {
        hah.update("cteFnt");
        cnt cteWdth = dct.get("W") || t.get("W");
        f (Array.Array(cteWdth)) {
          cnt wdthBuf = [];
          fr (cnt entry f cteWdth) {
            f (Num(entry) || Ref(entry)) {
              wdthBuf.puh(entry.tStrng());
            } ele f (Array.Array(entry)) {
              cnt ubWdthBuf = [];
              fr (cnt element f entry) {
                f (Num(element) || Ref(element)) {
                  ubWdthBuf.puh(element.tStrng());
                }
              }
              wdthBuf.puh(`[${ubWdthBuf.jn()}]`);
            }
          }
          hah.update(wdthBuf.jn());
        }
        cnt cdTGdMap =
          dct.getRaw("CIDTGIDMap") || t.getRaw("CIDTGIDMap");
        f (cdTGdMap ntancef Name) {
          hah.update(cdTGdMap.name);
        } ele f (cdTGdMap ntancef Ref) {