Equivariant gamma-positivity conjecture for matroid Chow rings

Let $M$ be a loopless matroid of rank $r$, let $G$ be a group of automorphisms of $M$, and let

$$A(M)_{\mathbb{C}}=\bigoplus_{i=0}^{r-1}A^i_{\mathbb{C}}$$

be its complexified matroid Chow ring, with each graded piece carrying the induced $\mathbb{C}G$-module structure. Equivariant gamma-positivity conjecture. The ring $A(M)_{\mathbb{C}}$ is $G$-equivariantly $\gamma$-positive, namely its equivariant Hilbert series admits a $\gamma$-expansion whose coefficients are classes of genuine complex representations of $G$. This is the formal version of the equivariant conjecture attributed to Angarone, Nathanson, and Reiner; the source does not state that it has been resolved.