MAYBE Proof: ConCon could not decide confluence of the system. \cite{ALS94}, Theorem 4.1 does not apply. \cite{A14}, Theorem 11.5.9 does not apply. \cite{O02}, p. 214, Proposition 7.2.50 does not apply. \cite{O02}, p. 214, Proposition 7.2.50 does not apply.