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)

const bounds = boxes.map(function (box, i) {
    return {
      x1: box.left,
      y1: box.top,
      x2: box.right,
      y2: box.bottom,
      index: i,
      x1New: undefined,
      x2New: undefined,
    };
  });
  expandBoundsLTR(width, bounds);
  const expanded = new Array(boxes.length);
  for (const b of bounds) {
    const i = b.index;
    expanded[i] = {
      left: b.x1New,
      top: 0,
      right: b.x2New,
      bottom: 0,
    };
  }
  
  
  boxes.map(function (box, i) {
    const e = expanded[i],
      b = bounds[i];
    b.x1 = box.top;