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)

figures,
          shadingFill ? null : background,
          owner.cachedCanvases
        );
        if (!shadingFill) {
          ctx.setTransform.apply(ctx, owner.baseTransform);
          if (matrix) {
            ctx.transform.apply(ctx, matrix);
          }
        }
        ctx.translate(
          temporaryPatternCanvas.offsetX,
          temporaryPatternCanvas.offsetY
        );
        ctx.scale(temporaryPatternCanvas.scaleX, temporaryPatternCanvas.scaleY);
        return ctx.createPattern(temporaryPatternCanvas.canvas, "no-repeat");
      },
    };
  },
};
ShadingIRs.Dummy = {
  fromIR: function Dummy_fromIR() {
    return {
      getPattern: function Dummy_fromIR_getPattern() {
        return "hotpink";
      },
    };
  },
};
function getShadingPatternFromIR(raw) {