Sorry for bothering again, I just encounter the similar issue in React,
issue codesandbox:
https://codesandbox.io/s/20221109-react-gsap-pin-ycfgno
when I wanted to pin sections in order by following the demo code: https://codepen.io/GreenSock/pen/KKpLdWW),
the last section was always covered.
I also canceled the strict mode in React, but it didn't help.