Attach (recommended) or Link to PDF file here:
http://help.adobe.com/en_US/livecycle/11.0/SampleForms/941/Form.pdf

- Web browser and its version: Firefox 89.0.1
- Operating system and its version: Windows 10 10.0.19043.1052
- PDF.js version: commit bdfcdd6f8326f22c135edfa29a341ea4c558f3d1
- Is a browser extension: No

Steps to reproduce the problem:
1. Enable XFA support
2. Open form

What is the expected behavior? (add screenshot)
Page 3 (of 4) renders
![image](https://user-images.githubusercontent.com/7104454/122686842-622e9980-d1e1-11eb-92ab-86fe488560f2.png)

What went wrong? (add screenshot)
Only 3 pages total render in pdf.js
const tree = new StructTreePage(structTreeRoot, this.pageDict);
    tree.parse();
    return tree;
  }
  getAnnotationsData(intent) {
    return this._parsedAnnotations.then(function (annotations) {
      const annotationsData = [];
      for (let i = 0, ii = annotations.length; i < ii; i++) {
        
        
        if (
          !intent ||
          (intent === "display" && annotations[i].viewable) ||
          (intent === "print" && annotations[i].printable)
        ) {
          annotationsData.push(annotations[i].data);
        }
      }
      return annotationsData;
    });
  }
  get annotations() {