Copyright on art gets more interesting / fuzzier. The key part is substantial similarity - https://en.wikipedia.org/wiki/Substantial_similarity and https://www.photoattorney.com/copyright-infringement-for-sub...
Rather than text, my AI copyright hypothetical... consider a model created based on sunset photographs. You take a regular photograph, pass it through the model, and it transforms it into a sunset. The model was trained on copyrighted works but the model is considered fair use.
Now, I go and take a photograph from some location during the day and then pass it through the transformer and get a sunset. Yea me! Unbeknownst to me, that location is a favorite location for photographers and there were sunsets from that location used in the training data. My photograph, transformed to look like a sunset is now similar to one of them in the training data.
Is my transformed photograph a derivative work of the one in the training data to which it bears similarity to? How would a judge feel about it? How does the photographer who's photograph was used in the training data feel?
Maybe it needs to be paired with another network / hunk of code that checks for verbatim copying?