Our uses of TweenMax all ignore the return object and use the static form. We don't new Tween() anythere.
In the case above there are several set() calls on the element:
TweenMax.set(htmlElement as any, { x: viewModel.left, y: viewModel.top, width: viewModel.width, height: viewModel.height, background: viewModel.background, position: 'absolute' });
TweenMax.set(this.domElement as any, {x: value});
TweenMax.set(this.domElement as any, { y: value });
TweenMax.set(this.domElement as any, { width: value });
TweenMax.set(this.domElement as any, { height: value });
None take the return value.
I have tried TweenMax.killAll() to try removing the window.CSSPlugin cached element.