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.paintChar(
                accent.fontChar,
                scaledAccentX,
                scaledAccentY,
                patternTransform,
                resetLineWidthToOne
              );
            }
          }
        }
        let charWidth;
        if (vertical) {
          charWidth = width * widthAdvanceScale - spacing * fontDirection;
        } else {
          charWidth = width * widthAdvanceScale + spacing * fontDirection;
        }
        x += charWidth;
        if (restoreNeeded) {
          ctx.restore();
        }
      }
      if (vertical) {
        current.y -= x;
      } else {
        current.x += x * textHScale;
      }
      ctx.restore();
      return undefined;
    }
    showType3Text(glyphs) {