Where am I supposed to look in that pdf to understand that it isn't correct or credible? It is certainly true that the model has differentiable and thus optimizable outputs.
Either way, if the claim is that it’s possible to reverse engineer CSAM from the hashes, proof is needed, and nobody has provided even a proof of concept.
The person I responded to was claiming it had been demonstrated. I asked for a link to evidence. You just made a hypothesis about how it might work. That’s not helpful.