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)

case "BM":
          this.ctx.globalCompositeOperation = value;
          break;
        case "SMask":
          if (this.current.activeSMask) {
            
            
            
            if (
              this.stateStack.length > 0 &&
              this.stateStack[this.stateStack.length - 1].activeSMask ===
                this.current.activeSMask
            ) {
              this.suspendSMaskGroup();
            } else {
              this.endSMaskGroup();
            }
          }
          this.current.activeSMask = value ? this.tempSMask : null;
          if (this.current.activeSMask) {
            this.beginSMaskGroup();
          }
          this.tempSMask = null;
          break;
        case "TR":
          this.current.transferMaps = value;
      }
    }
  }
  beginSMaskGroup() {