Previdi's delooping conjecture for exact categories

Let $\mathcal{A}$ be an exact category. Write $S(\mathcal{A})$ for the geometric realization of the simplicial category $iS_{\bullet}(\mathcal{A})$ given by Waldhausen's $S_{\bullet}$-construction. The category $\mathcal{A}$ is partially abelian if it and its opposite have pullbacks of admissible monomorphisms with common target. Write $\displaystyle\lim_{\longleftrightarrow}\mathcal{A}$ for Beilinson's category of generalized Tate objects associated to $\mathcal{A}$. The homotopy groups of the loop space of $S(\mathcal{A})$ are the algebraic $K$-theory groups of $\mathcal{A}$. Previdi's delooping conjecture. If $\mathcal{A}$ is partially abelian, then $S(\mathcal{A})$ is delooped by $S(\displaystyle\lim_{\longleftrightarrow}\mathcal{A})$. This conjecture proposes a delooping relation between the Waldhausen space of an exact category and that of its category of generalized Tate objects; the paper's abstract says that it proves a modified version using non-connective $K$-theory spectra, so the precise original formulation should be checked against that modification.