The formal expansion kernel conjecture for logarithmic crystalline cohomology

Let $X$ be a smooth toric variety of dimension $n$, let $Y$ be a smooth hypersurface, and consider logarithmic crystalline cohomology $H^n_{\operatorname{cris}}(X_0,Y_0)$ together with the formal expansion map

$$P\colon H^n_{\operatorname{DR}}(X,Y)\otimes R_\infty\to H^n_{\operatorname{DR}}(R_\infty[[t_1,\ldots,t_n]]/R_\infty).$$

Let $U_{\leq n-1}$ denote the slope-at-most-$n-1$ subcrystal. The formal expansion kernel conjecture. $U_{\leq n-1}$ is the kernel of the formal expansion map $P$. This conjecture identifies the slope filtration piece with the classes vanishing under local formal expansion, linking the Hodge-theoretic slope decomposition to Katz's local expansion method. The supplied text does not state whether the conjecture has been resolved.