Morales–Mészáros conjecture for type C Chan–Robbins–Yuen polytopes

Let $K^{C}_{n+1}$ be the complete signed graph with $n+1$ vertices, containing all edges $(i,j,\pm)$ for $1\leq i<j\leq n+1$ and $(i,i,+)$ for $1\leq i\leq n$, and let $\mathcal{F}_{K_{n+1}^{C}}(2,0,\ldots,0)$ be its flow polytope. Write $\operatorname{Cat}(k)=\frac{1}{k+1}\binom{2k}{k}$ for the $k$th Catalan number. Morales–Mészáros's type C volume conjecture. The normalized volume of $CRYC_{n+1}=\mathcal{F}_{K_{n+1}^{C}}(2,0,\ldots,0)$ is

$$\operatorname{vol}(CRYC_{n+1})=2^{n(n-1)}\prod_{k=0}^{n-1}\operatorname{Cat}(k).$$

This is a type C analogue of the Chan–Robbins–Yuen volume formula, predicting a power of $2$ times a product of consecutive Catalan numbers. The source presents it as Conjecture 7.8 of Morales and Mészáros; no resolution is supplied here.