Huang–Jiang's nonnegativity conjecture for torus-link zeta functions

Let $R^{(2,2k)}$ be the germ of the plane curve singularity $y(y-x^k)=0$, let $R^{(2,2k)\oplus N}$ denote the direct sum of $N$ copies of this singularity, and let $N\!Z_{R^{(2,2k)\oplus N}}(t)$ and $\widehat{N\!Z}_{R^{(2,2k)}}(t)$ be the corresponding zeta functions. Regard these functions after replacing $t$ by $-t$ as series in $t$ and $\mathbb{L}$. Huang–Jiang's nonnegativity conjecture. The zeta functions $N\!Z_{R^{(2,2k)\oplus N}}(-t)$ and $\widehat{N\!Z}_{R^{(2,2k)}}(-t)$, as series in $t$ and $\mathbb{L}$, have nonnegative coefficients.

This conjecture asserts coefficientwise nonnegativity for both the ordinary and motivic zeta functions in the even torus-link case. It is attributed in the source to Huang and Jiang's Conjecture 9.13; no resolution is given in the supplied material.