Singularities of divisors on flag varieties via Hwang's product theorem

We give an alternative proof of a recent result by Pasquier stating that for a generalized flag variety $X=G\mathrm{/}P$ and an effective $\mathbb{Q}$-divisor $D$ stable with respect to a Borel subgroup the pair $(X,D)$ is Kawamata log terminal if and only if $\lfloor D\rfloor =0$.