I suppose. There's no "air gap" between the copyrighted media being fed into its databanks and what it produces, which is going to make it easy to make the case that it's just grinding up and spitting out exactly what was put in, even if the results look indistinguishable from human-made transformative media.
Alternatively I could see them being pressured into admitting that, yes, fan art is technically copyright infringement too, but they just don't care enough to go after that and it's not like the law requires them to. I've been saying that for ages but it'd be nice to get official confirmation.