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 actions = collectActions(
      this.xref,
      this.pageDict,
      PageActionEventType
    );
    return shadow(this, "jsActions", actions);
  }
}
const PDF_HEADER_SIGNATURE = new Uint8Array([0x25, 0x50, 0x44, 0x46, 0x2d]);
const STARTXREF_SIGNATURE = new Uint8Array([
  0x73, 0x74, 0x61, 0x72, 0x74, 0x78, 0x72, 0x65, 0x66,
]);
const ENDOBJ_SIGNATURE = new Uint8Array([0x65, 0x6e, 0x64, 0x6f, 0x62, 0x6a]);
const FINGERPRINT_FIRST_BYTES = 1024;
const EMPTY_FINGERPRINT =
  "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
const PDF_HEADER_VERSION_REGEXP = /^[1-9]\.[0-9]$/;
function find(stream, signature, limit = 1024, backwards = false) {