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)

tmpCtx = tmpCanvas.context;
        putBinaryImageData(tmpCtx, imgData, this.current.transferMaps);
        imgToPaint = tmpCanvas.canvas;
      }
      let paintWidth = width,
        paintHeight = height;
      let tmpCanvasId = "prescale1";
      
      
      
      while (
        (widthScale > 2 && paintWidth > 1) ||
        (heightScale > 2 && paintHeight > 1)
      ) {
        let newWidth = paintWidth,
          newHeight = paintHeight;
        if (widthScale > 2 && paintWidth > 1) {
          newWidth = Math.ceil(paintWidth / 2);
          widthScale /= paintWidth / newWidth;
        }
        if (heightScale > 2 && paintHeight > 1) {
          newHeight = Math.ceil(paintHeight / 2);
          heightScale /= paintHeight / newHeight;
        }
        tmpCanvas = this.cachedCanvases.getCanvas(
          tmpCanvasId,
          newWidth,
          newHeight
        );
        tmpCtx = tmpCanvas.context;