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)

const BORDER_SIZE = 2;
    const offsetX = Math.floor(bounds[0]);
    const offsetY = Math.floor(bounds[1]);
    const boundsWidth = Math.ceil(bounds[2]) - offsetX;
    const boundsHeight = Math.ceil(bounds[3]) - offsetY;
    const width = Math.min(
      Math.ceil(Math.abs(boundsWidth * combinesScale[0] * EXPECTED_SCALE)),
      MAX_PATTERN_SIZE
    );
    const height = Math.min(
      Math.ceil(Math.abs(boundsHeight * combinesScale[1] * EXPECTED_SCALE)),
      MAX_PATTERN_SIZE
    );
    const scaleX = boundsWidth / width;
    const scaleY = boundsHeight / height;
    const context = {
      coords,
      colors,
      offsetX: -offsetX,
      offsetY: -offsetY,
      scaleX: 1 / scaleX,
      scaleY: 1 / scaleY,
    };
    const paddedWidth = width + BORDER_SIZE * 2;
    const paddedHeight = height + BORDER_SIZE * 2;
    const tmpCanvas = cachedCanvases.getCanvas(
      "mesh",
      paddedWidth,