Attach (recommended) or Link to PDF file here:
[Scan-to-Mail-PDF1_(1).pdf](https://github.com/mozilla/pdf.js/files/6876708/Scan-to-Mail-PDF1_.1.pdf)

Configuration:
- Web browser and its version: Firefox Developer 91.0b7 (64-Bit)
- Operating system and its version: Windows 10 (21H1)
- PDF.js version: 2.10.339 (also tested with the online demo, Version 2.11.5)
- Is a browser extension:

Steps to reproduce the problem:
1. Open the attached pdf
2. Scroll to page 3

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/7944797/126957487-cc7a2d19-adfb-42e4-9809-74e1a7a85048.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/7944797/126957351-29aebb4d-eadd-4273-b69d-530b9060c12c.png)




return promise;
  }
  getPageIndex(ref) {
    return this.messageHandler
      .sendWithPromise("GetPageIndex", {
        ref,
      })
      .catch(function (reason) {
        return Promise.reject(new Error(reason));
      });
  }
  getAnnotations(pageIndex, intent) {
    return this.messageHandler.sendWithPromise("GetAnnotations", {
      pageIndex,
      intent,
    });
  }
  saveDocument() {
    return this.messageHandler
      .sendWithPromise("SaveDocument", {
        isPureXfa: !!this._htmlForXfa,
        numPages: this._numPages,
        annotationStorage: this.annotationStorage.serializable,
        filename: this._fullReader?.filename ?? null,
      })
      .finally(() => {
        this.annotationStorage.resetModified();
      });
  }
  getFieldObjects() {