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
globalImageCache: this.globalImageCache,
        options: this.evaluatorOptions,
      });
      return partialEvaluator.getTextContent({
        stream: contentStream,
        task,
        resources: this.resources,
        normalizeWhitespace,
        includeMarkedContent,
        combineTextItems,
        sink,
      });
    });
  }
  async getStructTree() {
    const structTreeRoot = await this.pdfManager.ensureCatalog(
      "structTreeRoot"
    );
    if (!structTreeRoot) {
      return null;
    }
    const structTree = await this.pdfManager.ensure(this, "_parseStructTree", [
      structTreeRoot,
    ]);
    return structTree.serializable;
  }
  /**
   * @private
   */
  _parseStructTree(structTreeRoot) {