The Lorentzian conjecture for normalized Schur P-polynomials

Let $\lambda$ be a strict partition, meaning a decreasing sequence of positive integers, and let $P_\lambda(x_1,\ldots,x_m)$ be its Schur $P$-polynomial. Schur-$P$ conjecture. The normalized polynomial

$$\mathrm{N}(P_\lambda(x_1,\ldots,x_m))$$

is Lorentzian for every strict partition $\lambda$. The source gives computational evidence for small strict partitions and notes M-convexity of the support, but the Lorentzian assertion remains open.