Low rh in humidors

[Old Smokey]

Rh is much lower during the winter months and can cause problems. I agree that your humidors don't have a tight seal. Once you do the flashlight closet test, it usually takes very little to vastly improve the seal. Maybe Scotch tape around the seal would be the solution?

[Tombstone]

does the wood look dry? Winter will suck a lot of humidity from the wood. May be worth while to wipe them down a time or two to resaturate. That should help stabilize them a bit.