It clears up after several minutes I dont know what could be causing this. Car is always garaged when not being driven.
occasionally when I turn on the ac a horrible stink comes out of the vents. on 2004 Chrysler Crossfire
Your A/C evaporator drain could be blocked with debri and the water that condesates is not draining properly. After it sets in the case things start growing mold and fungus causing odor. Best to take to a shop so they lift it up to get access to drain to clean out and then sray a deoderant that kills fungus into air intakes to help combat the fungus.