Conjecture on the secrecy gain of formally unimodular lattices

Let $\Lambda$ be a formally unimodular lattice, with secrecy function $\Xi_{\Lambda}(\tau)$, and denote its secrecy gain by $\xi_{\Lambda}$. Formally unimodular secrecy-gain conjecture. The secrecy function of $\Lambda$ achieves its maximum at $\tau=1$, namely

$$\xi_{\Lambda}=\Xi_{\Lambda}(1).$$

The conjecture concerns whether the symmetry point remains the maximizing point for formally unimodular lattices, extending the preceding question beyond unimodular lattices; the source gives no resolution status.