I'm a GSAP noob. I was looking into how to create an animation that behaved slightly differently when you scroll back up rather than just reversing. I came across this forum post
which has this example: https://codepen.io/GreenSock/pen/eYJjxVb Although this showed me how to achieve what I was after, my version AND the example animation both exhibit the same unexpected behaviour as explained below . I've forked the example where I've simply increased the duration and the distance of movement, set all opacity occurrences to 1 and added markers. As expected, when you scroll down, the squares move up. When you scroll back up, the squares move back down.
To see the problem, rerun the animation and scroll down until the start marker just passes scroller-start. As soon as the left square starts to move, scroll back up a little bit until the start marker is just below scroller-start. What you should see is the square on the right moving up while the other two squares move down. Any help explaining why this happens would be appreciated.