Thank you @OSUblake for your reply, I fixed the codepen, and also modified the GSAP syntax as in the guide.
Still using my lottie file because I need something to click on to toggle the overflow visibility.
Good news, this problem is solved, I think it was bound to someting altering the dimensions of the body, and consequently the amount of scrollable space.
This problem is not yet been solved. If I try to scroll the animation till the end and click the pupil, overflow hides, but if I resize the browser window the scrollbar shows again.
For my project I need the overflow to stay hidden
Let me know if you have some clue
Thank you!:)
Fede