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)

xNew =
          affectedBoundary.index > boundary.index
            ? affectedBoundary.x1New
            : boundary.x1;
      } else if (affectedBoundary.x2New === undefined) {
        
        
        xNew = (affectedBoundary.x2 + boundary.x1) / 2;
      } else {
        
        xNew = affectedBoundary.x2New;
      }
      if (xNew > maxXNew) {
        maxXNew = xNew;
      }
    }
    
    boundary.x1New = maxXNew;
    
    for (q = i; q <= j; q++) {
      horizonPart = horizon[q];
      affectedBoundary = horizonPart.boundary;
      if (affectedBoundary.x2New === undefined) {
        
        if (affectedBoundary.x2 > boundary.x1) {
          
          
          if (affectedBoundary.index > boundary.index) {
            affectedBoundary.x2New = affectedBoundary.x2;
          }