computeIcrfToFixedMatrix returns undefined for valid JulianDate

CesiumJS
1

Good Morning,
I am receiving undefined as the return value when executing the following code:

const processPoint = (
  stkOutput,
  trimmedLine,
  tmpArr,
  utcDt,
  ptInx,
  positionsOverTime,
  enableECF
) => {
  const offset = parseFloat(tmpArr[0]);
  const x = parseFloat(tmpArr[1]);
  const y = parseFloat(tmpArr[2]);
  const z = parseFloat(tmpArr[3]);
  const positionInECI = Cartesian3.fromElements(x, y, z);
  const julianDate = JulianDate.fromDate(Moment.utc(utcDt).toDate());
  const dtOffset = JulianDate.addSeconds(julianDate, offset, new JulianDate());

  if (enableECF) {
    // Compute the transformation matrix from the ICRF to the ECEF frame at the given time.
    // This accounts for gmst.
    const fixedFrameTransform = Transforms.computeIcrfToFixedMatrix(dtOffset);
    //HERE is always undefined

Where dtOffset is

dtOffset: JulianDate
 dayNumber: 2460215
 secondsOfDay: 21818
// Wed Sep 27 2023 14:03:00 GMT-0400 (Eastern Daylight Time)

Lastly, after checking the chrome debugger, I am sure I am loading the IAU2006_XYS_18.js file.

I was wondering if someone here might see my mistake or suggest debugging methods?

Additional debugging:

function findSuccessfulMatrix(startJulianDate, numDays) {
  // Get the day and seconds of day for the start Julian date
  const startDay = startJulianDate.dayNumber;
  const startSec = startJulianDate.secondsOfDay;

  // Loop over the specified number of days
  for (let i = 0; i <= numDays; i++) {
    // Compute the current day and seconds of day
    const currentDay = startDay + i;
    const currentSec = startSec;

    // Get the Julian date for the current day and seconds of day
    const currentDate = getJulianDate(currentDay, currentSec);

    // Compute the ICRF to Fixed matrix for the current date
    const currentFixedFrameTransform = Transforms.computeIcrfToFixedMatrix(
      currentDate
    );

    // Check if the ICRF to Fixed matrix is defined
    if (currentFixedFrameTransform) {
      debugDtOffset('First successful transform at: ', currentDate);
      return;
    }
  }

  console.log('No successful transform found in the specified number of days.');
}

To display text output:

function debugDtOffset(msg, cesiumJulianDate) {
  // Convert the Cesium JulianDate to a JavaScript Date object
  const gregorianDate = JulianDate.toDate(cesiumJulianDate);
  // eslint-disable-next-line no-console
  console.log(`${msg}  ${gregorianDate}`);
  return gregorianDate;
}

Called like:

findSuccessfulMatrix(dtOffset, 365);

where dtOffset is as above:

JulianDate:
dayNumber: 2460215
secondsOfDay: 21817

First successful transform at: Sun Mar 31 2024 14:03:37 GMT-0400 (Eastern Daylight Time)

My input file contains dates starting at:
Wed Sep 27 2023 14:03:00 GMT-0400 (Eastern Daylight Time)

Could I be missing some other IAU200? file?

Last addition.

    const dummyOne = getJulianDate(2460405, 46837);
    const dummyOneFixedFrameTransform = Transforms.computeIcrfToFixedMatrix(
      dummyOne
    );
    const dummyTwo = getJulianDate(2460215, 21817);
    const dummyTwoFixedFrameTransform = Transforms.computeIcrfToFixedMatrix(
      dummyTwo
    );

dummyOne works, while dummyTwo is undefined.

Thanks again.
sg