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)

return undefined;
      }
      const ctx = this.ctx;
      const fontSizeScale = current.fontSizeScale;
      const charSpacing = current.charSpacing;
      const wordSpacing = current.wordSpacing;
      const fontDirection = current.fontDirection;
      const textHScale = current.textHScale * fontDirection;
      const glyphsLength = glyphs.length;
      const vertical = font.vertical;
      const spacingDir = vertical ? 1 : -1;
      const defaultVMetrics = font.defaultVMetrics;
      const widthAdvanceScale = fontSize * current.fontMatrix[0];
      const simpleFillText =
        current.textRenderingMode === TextRenderingMode.FILL &&
        !font.disableFontFace &&
        !current.patternFill;
      ctx.save();
      let patternTransform;
      if (current.patternFill) {
        
        
        ctx.save();
        const pattern = current.fillColor.getPattern(ctx, this);
        patternTransform = ctx.mozCurrentTransform;
        ctx.restore();
        ctx.fillStyle = pattern;
      }
      ctx.transform.apply(ctx, current.textMatrix);
      ctx.translate(current.x, current.y + current.textRise);