Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Chrome 90.0.4430.93
- Operating system and its version: macOs Big Sur 11.2.3
- PDF.js version: 2.7.570
- Is a browser extension: No

Steps to reproduce the problem:
1. Load the attached pdf in https://mozilla.github.io/pdf.js/web/viewer.html
2. Go to page 46. Dotted lines are missing in the graphics (see screenshot from acrobat reader)

What is the expected behavior? (add screenshot) See the screenshot
[Technical_Guide_UK.pdf](https://github.com/mozilla/pdf.js/files/6413001/Technical_Guide_UK.pdf)
![Screenshot 2021-05-03 at 07 46 09](https://user-images.githubusercontent.com/3785784/116844541-a343fd80-abe3-11eb-94c3-d03b3dfd6769.png)

);
            j += 6;
            break;
          case OPS.curveTo2:
            ctx.bezierCurveTo(
              x,
              y,
              args[j],
              args[j + 1],
              args[j + 2],
              args[j + 3]
            );
            x = args[j + 2];
            y = args[j + 3];
            j += 4;
            break;
          case OPS.curveTo3:
            x = args[j + 2];
            y = args[j + 3];
            ctx.bezierCurveTo(args[j], args[j + 1], x, y, x, y);
            j += 4;
            break;
          case OPS.closePath:
            ctx.closePath();
            break;
        }
      }
      current.setCurrentPoint(x, y);
    }
    closePath() {