The $t$-adic refinement of Kaneko–Zagier's conjecture

Let $\mathcal{Z}_{\widehat{\mathcal{A}}}$ be the $\boldsymbol{p}$-adically complete $\mathbb{Q}$-subalgebra of $\widehat{\mathcal{A}}$ generated by the $\widehat{\mathcal{A}}$-multiple zeta values and $\boldsymbol{p}$, and equip it with its $\boldsymbol{p}$-adic topology. Let $\overline{\mathcal{Z}}\llbracket t\rrbracket$ have its $t$-adic topology. Write $\zeta^{}_{\widehat{\mathcal{A}}}(\boldsymbol{k})$ and $\zeta^{}_{\widehat{\mathcal{S}}}(\boldsymbol{k})$ for the truncated $p$-adic and symmetric multiple zeta values, respectively.

The $t$-adic refinement. There is a topological $\mathbb{Q}$-algebra isomorphism from $\mathcal{Z}_{\widehat{\mathcal{A}}}$ onto $\overline{\mathcal{Z}}\llbracket t\rrbracket$ which sends

$$\zeta^{}_{\widehat{\mathcal{A}}}(\boldsymbol{k})\mapsto\zeta^{}_{\widehat{\mathcal{S}}}(\boldsymbol{k}),\qquad \boldsymbol{p}\mapsto t.$$

This is presented as a refinement of the Kaneko–Zagier conjecture to the truncated $t$-adic setting. The supplied text does not state whether it is open, solved, or refuted.