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
)
            .catch(function (reason) {
              warn(`loadXfaFonts: "${reason}".`);
              return null;
            })
        );
      }
    }
    await Promise.all(promises);
    this.xfaFactory.appendFonts(pdfFonts);
  }
  async serializeXfaData(annotationStorage) {
    if (this.xfaFactory) {
      return this.xfaFactory.serializeData(annotationStorage);
    }
    return null;
  }
  get formInfo() {
    const formInfo = {
      hasFields: false,
      hasAcroForm: false,
      hasXfa: false,
      hasSignatures: false,
    };
    const acroForm = this.catalog.acroForm;
    if (!acroForm) {
      return shadow(this, "formInfo", formInfo);
    }
    try {
      const fields = acroForm.get("Fields");