Thank you for fast response!
I made another pen so you could get the idea of what I'm trying to do. When user clicks on envelope icon , div that contains it scales up and transforms to a rectangle and form fades in(left some parts out of the pen). I didn't use scroll trigger, because I don't want the ball div to get back in position while it is scaled if user opens form(scales up ball) for example in mid-page and scrolls back to top with ball being scaled-up.
As for using invalidate(), this is best I could come up with, it resets starting position, which is exactly what I wanted but popFormTl.reverse() doesn't work 2nd time.
If I could get some hint how to make it work more than once, I would be thankful.
As for Flip Plugin I definitely will take a look, but at the moment I am not a member of Club GreenSock(I think it is only matter of time, cause I enjoy GSAP more and more), so it will not be used in this project.
https://codepen.io/Fishers666/pen/oNWmBVd?editors=1111