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)

height,
          true
        );
        this.compositeCtx = this.ctx;
        this.transparentCanvas = transparentCanvas.canvas;
        this.ctx = transparentCanvas.context;
        this.ctx.save();
        
        
        this.ctx.transform.apply(
          this.ctx,
          this.compositeCtx.mozCurrentTransform
        );
      }
      this.ctx.save();
      resetCtxToDefault(this.ctx);
      if (transform) {
        this.ctx.transform.apply(this.ctx, transform);
      }
      this.ctx.transform.apply(this.ctx, viewport.transform);
      this.baseTransform = this.ctx.mozCurrentTransform.slice();
      this._combinedScaleFactor = Math.hypot(
        this.baseTransform[0],
        this.baseTransform[2]
      );
      if (this.imageLayer) {
        this.imageLayer.beginLayout();
      }
    }
    executeOperatorList(