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)

this.restore();
    }
    beginAnnotation(rect, transform, matrix) {
      this.save();
      resetCtxToDefault(this.ctx);
      this.current = new CanvasExtraState();
      if (Array.isArray(rect) && rect.length === 4) {
        const width = rect[2] - rect[0];
        const height = rect[3] - rect[1];
        this.ctx.rect(rect[0], rect[1], width, height);
        this.clip();
        this.endPath();
      }
      this.transform.apply(this, transform);
      this.transform.apply(this, matrix);
    }
    endAnnotation() {
      this.restore();
    }
    paintImageMaskXObject(img) {
      if (!this.contentVisible) {
        return;
      }
      const ctx = this.ctx;
      const width = img.width,
        height = img.height;
      const fillColor = this.current.fillColor;