Demazure crystal structure for flagged reverse plane partitions

Given a skew shape \( \lambda / \mu \) and a flag \(\Phi,\) we show that the set of all flagged reverse plane partitions of shape \(\lambda / \mu\) and flag \(\Phi\) is a disjoint union of Demazure crystals (up to isomorphism). As a result, the flagged dual stable Grothendieck polynomial \( g_{\lambda/\mu}(X_\Phi)\) is shown to be key positive.