Fenn–Kauffman–Manturov bracket-polynomial conjecture for virtual knots

Let $K$ be a virtual knot, and let $\langle K\rangle$ denote its bracket polynomial. Two virtual knots are Z-equivalent when they are related by classical and virtual Reidemeister moves together with the Z-move.

Fenn–Kauffman–Manturov conjecture. If

$$\langle K\rangle=1,$$

then $K$ is Z-equivalent to the unknot.

This conjecture, attributed in the source to Fenn, Kauffman, and Manturov, asserts that the bracket polynomial detects the unknot up to Z-equivalence in the value-one case. The source does not give a resolution.