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)

}
      bufferLength -= n;
      this.bufferLength = bufferLength;
      this.buffer = buffer & ((1 << bufferLength) - 1);
      return buffer >> bufferLength;
    },
    align: function MeshStreamReader_align() {
      this.buffer = 0;
      this.bufferLength = 0;
    },
    readFlag: function MeshStreamReader_readFlag() {
      return this.readBits(this.context.bitsPerFlag);
    },
    readCoordinate: function MeshStreamReader_readCoordinate() {
      const bitsPerCoordinate = this.context.bitsPerCoordinate;
      const xi = this.readBits(bitsPerCoordinate);
      const yi = this.readBits(bitsPerCoordinate);
      const decode = this.context.decode;
      const scale =
        bitsPerCoordinate < 32
          ? 1 / ((1 << bitsPerCoordinate) - 1)
          : 2.3283064365386963e-10; 
      return [
        xi * scale * (decode[1] - decode[0]) + decode[0],
        yi * scale * (decode[3] - decode[2]) + decode[2],
      ];
    },
    readComponents: function MeshStreamReader_readComponents() {
      const numComps = this.context.numComps;
      const bitsPerComponent = this.context.bitsPerComponent;