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

let saveIndex = 0;
      if (items.children.length === 2) {
        displayedIndex = items.children[0].save;
        saveIndex = 1 - displayedIndex;
      }
      const displayed = items.children[displayedIndex][$toHTML]().html;
      const values = items.children[saveIndex][$toHTML]().html;
      let selected = false;
      const value = (field.value && field.value[$text]()) || "";
      for (let i = 0, ii = displayed.length; i < ii; i++) {
        const option = {
          name: "option",
          attributes: {
            value: values[i] || displayed[i],
            style: optionStyle,
          },
          value: displayed[i],
        };
        if (values[i] === value) {
          option.attributes.selected = selected = true;
        }
        children.push(option);
      }
      if (!selected) {
        children.splice(0, 0, {
          name: "option",
          attributes: {
            hidden: true,
            selected: true,
          },