All containers new, from 3 different sources. No common sticks to all containers. Combo of KL and Boveda packs in all containers. I am with you, there MUST be a common factor.
UPDATE: As of this afternoon, only one container, the one with the strongest odor, still has the sour smell. The others have all dissipated. One of them is beginning to pick up the cedar smell and the others just smell like tobacco. So only one still has the problem...now, do I just give it more time or do I pick up 2 more containers and divide the sour one into the three with KL in one, Boveda in another and both in the third?