Calling tween.stop() should stop the tween, and a following tween.update(time) (f.e. in an animation frame) should return false so that the return value is reliable for exiting the animation loop. Currently this will fail:

function loop(time) {
  const keepGoing = tween.update(time)
  if (keepGoing) requestAnimationFrame(loop)
}

loop(performance.now())

// ... later, before the animation is finished ...
tween.stop() // Does not cause the loop to stop, the loop keeps going.

The tween.stop() call should cause tween.update() to return true so that the animation loop will end.