I have been using kitty litter for RH control. It has worked well in all three of of my humidors.

I don't have any additional fans for air flow, just the main fan for the unit.

The drawers are John Nelson's. They are well slotted, leave room at the back for air flow and have an air space on the back "wall" of the drawers for additional air flow.

The main source of RH control is in the bottom drawer. Tupperware filled with KL. I also have two smaller containers of KL in the Wineador, one near the middle, one near the top.

The affected cigars were in two drawers. Two were in the drawer directly above the main KL, three were in the next drawer up (my Queen B's).

The KL did not seem to be too moist, I have not added water in months. Do you think it could still be letting off enough water vapor to cause this?