I've been noticing recently that when I open my tupperdors there is a slightly sour odor present. I have strips of cedar in the bottom and even have a cedar humidor tray in one of them and all are showing the same thing. I'm using 65% Boveda packs and KL and all are coming in at a solid 65% rh at about 70F. Anyone else have this issue? Any ideas about the cause?