The claim in TFA is that the formalization(in Lean) of the problem does not correspond to the natural language statement of the problem, such that the statement proven is not the conjecture for which proof is required for the problem to be considered "solved".
Does that contradict what I said? In that quote, it says that the NL proof does not correspond to the Lean proof. However, the statement of the theorem in Lean is independent from the NL proof. It comes from a DeepMind repository, which as far as I'm aware has been accepted by the community as a valid formalization of the original Clay Institute statement.