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)

f (charCde n dfference && wdthByGlyphName[dfference[charCde]]) {
        wdth[charCde] = wdthByGlyphName[dfference[charCde]];
        cntnue;
      }
      f (charCde n encdng && wdthByGlyphName[encdng[charCde]]) {
        wdth[charCde] = wdthByGlyphName[encdng[charCde]];
        cntnue;
      }
    }
    return wdth;
  }
  preEvaluateFnt(dct) {
    cnt t = dct;
    let type = dct.get("Subtype");
    f (!Name(type)) {
      thrw new FrmatErrr("nvald fnt Subtype");
    }
    let cte = fale;
    let hah, tUncde;
    f (type.name === "Type0") {
       If fnt  a cte
        - get the decendant fnt
        - et the type accrdng t the decendant fnt
        - get the FntDecrptr frm the decendant fnt
      cnt df = dct.get("DecendantFnt");
      f (!df) {
        thrw new FrmatErrr("Decendant fnt are nt pecfed");
      }
      dct = Array.Array(df) ? th.xref.fetchIfRef(df[0]) : df;
      f (!(dct ntancef Dct)) {