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)

} else {
          affectedBoundary.x2New = maxXNew;
        }
      } else if (affectedBoundary.x2New > maxXNew) {
        
        affectedBoundary.x2New = Math.max(maxXNew, affectedBoundary.x2);
      }
    }
    
    const changedHorizon = [];
    let lastBoundary = null;
    for (q = i; q <= j; q++) {
      horizonPart = horizon[q];
      affectedBoundary = horizonPart.boundary;
      
      const useBoundary =
        affectedBoundary.x2 > boundary.x2 ? affectedBoundary : boundary;
      if (lastBoundary === useBoundary) {
        
        changedHorizon[changedHorizon.length - 1].end = horizonPart.end;
      } else {
        changedHorizon.push({
          start: horizonPart.start,
          end: horizonPart.end,
          boundary: useBoundary,
        });
        lastBoundary = useBoundary;
      }
    }
    if (horizon[i].start < boundary.y1) {