RepeatDelay is not working

I am trying to delay repeat loop in animations using repeatDelay but this isn't working
var tween = new TWEEN.Tween(o, timeline).to({ value: duration }, duration)
.onStart(function () {
mediaElements.forEach(async (x) => {
x.play();
}
}
.onComplete(function () {
mediaElements.forEach(async (x) => {
x.pause();
}
}
.onRepeat(function () {
elements.forEach(x => {
x.currentTime = 0;
x.play();
});
})
.repeat(loopCount == loopTypes.forever ? foreverLoop : loopCount - 1)
.repeatDelay(2000)

repeatDelay isn't working here

Start by reproducing the provided TWEEN snippet with repeatDelay(2000) and isolate whether the delay is missing from the animation loop. No source file or test is named in the issue, so inspect the repeatDelay implementation and existing repeat-related tests. Done means the reported animation repeats with the requested delay and coverage verifies the behavior.