Specifically within AFC, note the "idea/expression dichotomy" [1] which clearly states:
"copyright law protects an author's expression, but not the idea behind that expression"
Thus, if this tools spits out someone else's code verbatim it is a definite copyright infringement. If it outputs code that is similar but not verbatim then it "could" be an infringement, at your own risk, and to be determined by the courts. Simply expressing the same idea in a different way is not a definite infringement.
Program code is naturally copyright-risky because the keyword/grammar space is constrained. It is far more difficult to accidentally duplicate verbatim the expression of one's ideas in a full language, such as English, than in C. And what of two separate programs (or constituent sub-parts such as functions) that by chance emit the same compiled binary?
Personally, for now I won't use this tool due to the risk of accidental plagiarism, and because it is a black box: I can't examine any lineage or attribution metadata to understand the source(s) of what I would then be incorporating into my own body of work. Of course I doubt I could get that type of traceability information for any other trained ML model I might use, so perhaps I need to re-examine my policies heading into the future.
[1] https://en.wikipedia.org/wiki/Idea%E2%80%93expression_distin...