The most likely source of trouble is the cloth between the figure and the prop.
It will either be that they are too close and the simulation can't solve for the collision offset properly to both of them (which you might be able to rectify by reducing that value) or the figure and prop geometries actually intersect (which is an absolute no-no for the simulator, and once you cure that you'll be in the situation of needing to get an acceptable collision offset and geometry seperation as previously mentioned).