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._transformMatrix = old.slice(0, 6);
    this._originalSave();
  };
  ctx.restore = function ctxRestore() {
    const prev = this._transformStack.pop();
    if (prev) {
      this._transformMatrix = prev;
      this._originalRestore();
    }
  };
  ctx.translate = function ctxTranslate(x, y) {
    const m = this._transformMatrix;
    m[4] = m[0] * x + m[2] * y + m[4];
    m[5] = m[1] * x + m[3] * y + m[5];
    this._originalTranslate(x, y);
  };
  ctx.scale = function ctxScale(x, y) {
    const m = this._transformMatrix;
    m[0] = m[0] * x;
    m[1] = m[1] * x;
    m[2] = m[2] * y;
    m[3] = m[3] * y;
    this._originalScale(x, y);
  };
  ctx.transform = function ctxTransform(a, b, c, d, e, f) {
    const m = this._transformMatrix;
    this._transformMatrix = [
      m[0] * a + m[2] * b,
      m[1] * a + m[3] * b,
      m[0] * c + m[2] * d,