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)

if (isNum(glyph)) {
          spacingLength = (spacingDir * glyph * fontSize) / 1000;
          this.ctx.translate(spacingLength, 0);
          current.x += spacingLength * textHScale;
          continue;
        }
        const spacing = (glyph.isSpace ? wordSpacing : 0) + charSpacing;
        const operatorList = font.charProcOperatorList[glyph.operatorListId];
        if (!operatorList) {
          warn(`Type3 character "${glyph.operatorListId}" is not available.`);
          continue;
        }
        if (this.contentVisible) {
          this.processingType3 = glyph;
          this.save();
          ctx.scale(fontSize, fontSize);
          ctx.transform.apply(ctx, fontMatrix);
          this.executeOperatorList(operatorList);
          this.restore();
        }
        const transformed = Util.applyTransform([glyph.width, 0], fontMatrix);
        width = transformed[0] * fontSize + spacing;
        ctx.translate(width, 0);
        current.x += width * textHScale;
      }
      ctx.restore();
      this.processingType3 = null;
    }
    
    setCharWidth(xWidth, yWidth) {