BUG: Timestamp.toObject() returning zeroed value

In the latest version, 3.21.4, the Timestamp.toObject() function isn't working correctly.

Previously it would return the timestamp as an object with keys for seconds and milliseconds. However now it is returning zero values for both.

This is a function where I noticed the issue, I've added some logging which pointed out toObject() as being the problem.

function dateToTs(date: Date): Timestamp {
  const ts = new Timestamp();
  ts.fromDate(date);
  console.log(
    "date:",
    date,
    "timestamp:",
    ts.getSeconds(),
    ts.getNanos(),
    ts.toObject(),
  );
  return ts;
}

See the screenshot below for the resulting console log, where you can see the seconds and milliseconds are set, but the toObject return is zeroed

Start at Timestamp.toObject() and compare its result with getSeconds() and getNanos() when the value is created through fromDate(), using the dateToTs() example from the report. Reproduce the zeroed fields on version 3.21.4; done when toObject() returns the populated seconds and milliseconds values.