In the linked CodePen (and attached GIF) an item is rendered, a class is added, and then an animation is applied. The class changes the opacity to 0.5 and this works when it is applied and throughout the animation; however, after the animation the opacity changes even though the class is still applied. What's also odd is that as soon as I right-click the element in Chrome, the opacity takes affect!
Is there something going on with GSAP under the hood?