Parabolic restriction conjecture for crystalline monodromy groups

Let $f\colon V\hookrightarrow U$ be an open sub-curve, let $u\in V({\mathbb{F}}_{q^e})$ be a base point, and let ${\mathcal{F}}$ be a convergent $F$-isocrystal on $U$. Write $\operatorname{Gr}(f^*{\mathcal{F}}/V,u)$ and $\operatorname{Gr}({\mathcal{F}}/U,u)$ for the corresponding monodromy groups. Parabolic restriction conjecture. The subgroup

$$\operatorname{Gr}(f^*{\mathcal{F}}/V,u)\subset\operatorname{Gr}({\mathcal{F}}/U,u)$$

is parabolic. No conjectural label or status evidence is included in the supplied span, so the claim may require checking against the surrounding source text.