Red Giant Form shading wont work anymore?

What version of Form do you use? You try to use the latest version.

https://www.maxon.net/en/downloads

Being a third-party plugin, you might get a better answer direct from Maxon support.  They are pretty good at responding once you open a ticket.

I don't have Form myself, so can't give a more complete answer.  I take it you're on the latest version of both AE and Red Giant / Maxon One?  If so, did it work before upgrading?