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.ctx.lineCap = LINE_CAP_STYLES[style];
    }
    setLineJoin(style) {
      this.ctx.lineJoin = LINE_JOIN_STYLES[style];
    }
    setMiterLimit(limit) {
      this.ctx.miterLimit = limit;
    }
    setDash(dashArray, dashPhase) {
      const ctx = this.ctx;
      if (ctx.setLineDash !== undefined) {
        ctx.setLineDash(dashArray);
        ctx.lineDashOffset = dashPhase;
      }
    }
    setRenderingIntent(intent) {
      
    }
    setFlatness(flatness) {
      
    }
    setGState(states) {
      for (let i = 0, ii = states.length; i < ii; i++) {
        const state = states[i];
        const key = state[0];
        const value = state[1];
        switch (key) {
          case "LW":