Attach (recommended) or Link to PDF file here:
https://www.canada.ca/content/dam/ircc/migration/ircc/english/pdf/kits/forms/eimm5669e.pdf
[eimm5669e.pdf](https://github.com/mozilla/pdf.js/files/7225677/eimm5669e.2.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Linux Debian

Steps to reproduce the problem:
1. Look at the bottom of page 2

if (this.subform.children.length === 0) {
      warn("XFA - No subforms in template node.");
    }
    if (this.subform.children.length >= 2) {
      warn("XFA - Several subforms in template node: please file a bug.");
    }
    this[$tabIndex] = DEFAULT_TAB_INDEX;
  }
  [$isSplittable]() {
    return true;
  }
  [$searchNode](expr, container) {
    if (expr.startsWith("#")) {
      
      return [this[$ids].get(expr.slice(1))];
    }
    return searchNode(this, container, expr, true, true);
  }
  [$toHTML]() {