  In this note we prove that a conjectural formula for the class $\lambda_g
\mathrm{DR}_g(a,-a)\in R^{2g}(\overline{\mathcal{M}}_{g,2})$ proposed recently
by Buryak-Iglesias-Shadrin is true in the Gorenstein quotient of the ring
$R^*(\overline{\mathcal{M}}_{g,2})$. As a corollary we prove the strong
$\mathrm{DR} \backslash \mathrm{DZ}$ equivalence conjecture for one-point
correlators.
