In this technical note, we disprove S.-L. Chen's \cite{chen} assertion that
the generalized Hukuhara directional differentiability of an interval-valued
function defined on a Hadamard manifold is fully identical to the directional
differentiability of its endpoint functions by providing a counterexample.
Moreover, we address imprecisions in several results proved by using the
aforementioned assertion in \cite{chen}. We provide correct statements of the
imprecise results and construct examples in their support