Attach (recommended) or Link to PDF file here: [RenderIssue.pdf](https://github.com/mozilla/pdf.js/files/7583657/RenderIssue.pdf)

Configuration:
- Web browser and its version: Chrome Version 96.0.4664.45 (Official Build) (64-bit)
- Operating system and its version: Windows 10 Version 10.0.19042

- PDF.js version: v2.12.201 (If this looks incorrect, please take it from the URL)
- Is a browser extension: No, using https://mozilla.github.io/pdf.js/web/viewer.html

Steps to reproduce the problem:
1. Visit https://mozilla.github.io/pdf.js/web/viewer.html
2. Drop the attached PDF on to the page - [RenderIssue.pdf](https://github.com/mozilla/pdf.js/files/7583657/RenderIssue.pdf)

What is the expected behavior? It should appear as in Adobe Reader - 
![image](https://user-images.githubusercontent.com/94864394/142921185-1ee7034b-1db9-4b6d-ae08-4a9cb4426d70.png)

What went wrong? Some text is blank - 
![image](https://user-images.githubusercontent.com/94864394/142921086-a5ad3ad7-caac-40d8-92d3-684d59aee1f5.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): N/A

const minY = Math.round(y1),
    maxY = Math.round(y3);
  let xa, car, cag, cab;
  let xb, cbr, cbg, cbb;
  for (let y = minY; y <= maxY; y++) {
    if (y < y2) {
      let k;
      if (y < y1) {
        k = 0;
      } else {
        k = (y1 - y) / (y1 - y2);
      }
      xa = x1 - (x1 - x2) * k;
      car = c1r - (c1r - c2r) * k;
      cag = c1g - (c1g - c2g) * k;
      cab = c1b - (c1b - c2b) * k;
    } else {
      let k;
      if (y > y3) {
        k = 1;
      } else if (y2 === y3) {
        k = 0;
      } else {
        k = (y2 - y) / (y2 - y3);
      }
      xa = x2 - (x2 - x3) * k;
      car = c2r - (c2r - c3r) * k;
      cag = c2g - (c2g - c3g) * k;
      cab = c2b - (c2b - c3b) * k;
    }