Vanishing of the virtual Alexander polynomial for slice virtual knots

Let $K$ be a virtual knot, and let $H_K(s,t,q)$ denote its virtual Alexander polynomial.

Vanishing conjecture. If $K$ is slice, then

$$H_K(s,t,q)=0.$$

The polynomial was introduced as a slice obstruction, and it vanishes for all slice virtual knots currently known. Whether it vanishes for every slice virtual knot, and whether it is a concordance invariant, remains open.