I would try to add an obstacles at the position of non-moving characters.
(and of course, remove it before setting a new destination)
I believe, with a cylindrical obstacle with a radius of the same value as the agent, it should work.
but, I don’t know your use case. If there are 100s of characters, this might be an issue because of the obstacle count limit and the number of navmesh recomputation because of obstacles added/removed.