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 field = this.xref.fetchIfRef(fieldRef);
    if (field.has("T")) {
      const partName = stringToPDFString(field.get("T"));
      if (name === "") {
        name = partName;
      } else {
        name = `${name}.${partName}`;
      }
    }
    if (!promises.has(name)) {
      promises.set(name, []);
    }
    promises.get(name).push(
      AnnotationFactory.create(
        this.xref,
        fieldRef,
        this.pdfManager,
        this._localIdFactory,
         true
      )
        .then(annotation => annotation && annotation.getFieldObject())
        .catch(function (reason) {
          warn(`_collectFieldObjects: "${reason}".`);
          return null;
        })
    );
    if (field.has("Kids")) {
      const kids = field.get("Kids");
      for (const kid of kids) {
        this._collectFieldObjects(name, kid, promises);