Attach (recommended) or Link to PDF file here:
[multiple.pdf](https://github.com/mozilla/pdf.js/files/6344777/multiple.pdf)

Steps to reproduce the problem:
1. Write something in a field

What is the expected behavior? (add screenshot)
The 3 fields must have the same value

What went wrong? (add screenshot)
The 2 other fields are empty

The three fields share the same name `Text3`.
It works as expected in Adobe and Chrome.
const p = document.createElement("p");
    const lines = contents.split(/(?:\r\n?|\n)/);
    for (let i = 0, ii = lines.length; i < ii; ++i) {
      const line = lines[i];
      p.appendChild(document.createTextNode(line));
      if (i < ii - 1) {
        p.appendChild(document.createElement("br"));
      }
    }
    return p;
  }
  /**
   * Toggle the visibility of the popup.
   *
   * @private
   * @memberof PopupElement
   */
  _toggle() {