The symplectic-resolution conjecture for affine-Grassmannian slices

Let $G$ be the reductive group and let $\Grlmbar$ be the affine-Grassmannian slice under consideration. A symplectic resolution is a resolution of singularities whose pullback of the symplectic form on the smooth locus extends to a symplectic form on the resolution. The symplectic-resolution conjecture. Any symplectic resolution of $\Grlmbar$ is of the form

$$\Gr^{\overline{\vlam}}_\mu.$$

The claim proposes that the convolution varieties constructed in the paper exhaust all symplectic resolutions of these slices; the source gives no resolution or counterexample.