It clearly isn’t. Which is why clean-room reverse engineering always requires at least two people. Or why a musician that accidentally recreates a chord progression they heard years ago but don't remember the source might still get sued.
When I read and remember a text, possibly also learning from it, I'm not making a copy and I'm not creating a derivative work. The state of my brain is outside of copyright. Only at the point where I create a new representation based on what I have read I may be violating someone's copyrights.
But is it the same for an AI? Is the act of reading, remembering and learning (i.e. adjusting model weights) not in itself tantamount to creating a derivative work?
Is it actually? If we could fully pull out the state of your brain, and understand that you stored a copy of a copyrighted work, I think you could be on the hook for licensing it, paying fees every time you remember the work as a performance of it.
When a person learns from GPL code this question doesn't arise. The state of a person's brain is outside of copyright. But is the state of an LLM also outside of copyright or outside of the terms covered by the GPL? I'm not sure.
An LLM can not only emit source code derived from code published under the GPL, it can also potentially execute a program and could therefore be considered object code.
This isn't necessarily a problem as long as the model isn't distributed and does not include any AGPL code.