Finite-dimensionality criterion for local Picard groups of S2 surfaces

Let $(s,S)$ be an $S_2$ surface. Finite-dimensionality conjecture. There is a finite-dimensional local Picard group $\operatorname{\mathbf{Pic}}^{\rm loc}(s,S)$ if and only if $S$ is seminormal. The conjecture is motivated by the contrast between normal complex surface singularities, where finite-dimensional local Picard groups are known, and many non-normal examples in which no finite-dimensional local Picard group exists; its resolution is not supplied in the source.