Not sure what algorithm Deezer is using, but Benn Jordan is a fairly tech savvy musician who talks about ways to id AI generated music by looking for compression artifacts used by the training data.
https://youtu.be/QVXfcIb3OKo?si=74EdIey6RIhuwdzg
This is apparently how Deezer is doing it.
This is apparently how Deezer is doing it.