Word file used: 
[Formular_T.docx](https://github.com/mozilla/pdf.js/files/6907859/Formular_T.docx)

PDFs generated:
PDF 1: [Formular_T_default.pdf](https://github.com/mozilla/pdf.js/files/6907771/Formular_T_default.pdf)
PDF 2: [Formular_T_changed.pdf](https://github.com/mozilla/pdf.js/files/6907772/Formular_T_changed.pdf)

- PDF.js version: v2.9.359

Steps to reproduce the problem:
1. Create Word Document with Checkbox and check it.
2. Convert Word document to PDF using **Aspose.pdf** (for .net)

3. Extra: Change value of second Checkbox  in PDF 1 and save the file (PDF 2). The new File will show both Checkboxes checked in other browser, but only the newly checked one in PDF.js

Expected:
Checkbox is checked (pdf viewer from adobe/Chrome Version 92.0.4515.107 64-bit)
![image](https://user-images.githubusercontent.com/76941221/127659557-42be1cca-3c90-49b8-b224-70ee85aa1b30.png)

Result:
Checkbox is not checked (Mozilla Firefox/PDF.js)
![image](https://user-images.githubusercontent.com/76941221/127660064-e3cdc3f9-6887-4ae7-af27-d46cded69029.png)



constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.POPUP;
    let parentItem = parameters.dict.get("Parent");
    if (!parentItem) {
      warn("Popup annotation has a missing or invalid parent annotation.");
      return;
    }
    const parentSubtype = parentItem.get("Subtype");
    this.data.parentType = isName(parentSubtype) ? parentSubtype.name : null;
    const rawParent = parameters.dict.getRaw("Parent");
    this.data.parentId = isRef(rawParent) ? rawParent.toString() : null;
    const parentRect = parentItem.getArray("Rect");
    if (Array.isArray(parentRect) && parentRect.length === 4) {
      this.data.parentRect = Util.normalizeRect(parentRect);
    } else {
      this.data.parentRect = [0, 0, 0, 0];
    }
    const rt = parentItem.get("RT");
    if (isName(rt, AnnotationReplyType.GROUP)) {
      
      
      parentItem = parentItem.get("IRT");
    }
    if (!parentItem.has("M")) {
      this.data.modificationDate = null;
    } else {