Earlier quoted context omitted.
Interesting thought - doesn't every single porn producer now have a valid copyright claim on the trained network? I don't see how you can argue this isn't a derivative work based on the movies they produced.
I don't think it's a derivative work just because one of the inputs is copyrighted. I think it's more descriptive than derivative. Content producers don't generally own copyright in critics' descriptions of their movies or of plot summaries, even though their copyrighted material is a necessary input to the description's creation.
Also, good luck trying to prove that your film was used to train this network.