Attach (recommended) or Link to PDF file here:
https://s3.eu-west-1.amazonaws.com/scai-dev.website.com/tmp/8ab8b56a-fa91-11eb-8d74-0242ac110004.pdf

Hi,
Please see an incorrect canvas rendering for the following document - page 9 specifically. It reproduces on https://mozilla.github.io/pdf.js/web/viewer.html (tried with Chrome). Other pages in this document look pretty much the same but the problem is on page 9 only.

Original screenshot:
![image](https://user-images.githubusercontent.com/23075641/129066656-7bb2fb56-2b88-4f40-8e67-b95bdeb9e521.png)


PDF JS:

![image](https://user-images.githubusercontent.com/23075641/129066734-56503a5c-413c-49c1-9e1c-470da3a642ed.png)

_createMaskCanvas(img) {
    const ctx = this.ctx;
    const width = img.width,
      height = img.height;
    const fillColor = this.current.fillColor;
    const isPatternFill = this.current.patternFill;
    const maskCanvas = this.cachedCanvases.getCanvas(
      "maskCanvas",
      width,
      height
    );
    const maskCtx = maskCanvas.context;
    putBinaryImageMask(maskCtx, img);
    
    
    
    
    const objToCanvas = ctx.mozCurrentTransform;
    let maskToCanvas = Util.transform(objToCanvas, [
      1 / width,
      0,
      0,
      -1 / height,
      0,
      0,
    ]);
    maskToCanvas = Util.transform(maskToCanvas, [1, 0, 0, 1, 0, -height]);
    const cord1 = Util.applyTransform([0, 0], maskToCanvas);
    const cord2 = Util.applyTransform([width, height], maskToCanvas);
    const rect = Util.normalizeRect([cord1[0], cord1[1], cord2[0], cord2[1]]);