But in the present case the authorship is just removed by shredding the library and then piecing back together the sentences. The fact that under some circumstances AIs will happily reproduce code that was in the training data is proof positive they are to some degree lossy compressors. The more generic something is ("for (i=0;i<MAXVAL;i++) {") the lower the claim for copyright infringement. But higher level constructs past a couple of lines that are unique in the training set that are reproduced in the output modulo some name changes and/or language changes should count as automatic transformation (and hence infringing or creating a derivative work).
The people using GenAI should be the ones doing the verification. The maintainer's job should not meaningfully change (other than the maintainer using AI to review on incoming code, of course).
Why does everyone who hears "AI code" automatically think "vibe-coded"?