It seems like I am ALWAYS asking this question, but what kind of humidity measurement are you using?

I think I would get a larger humidor because think about how much room for air is actually in your little humidor. You open it up and that air is all likely displaced, so your humidity device has to re-humidify the air. Your humidor interior won't loose it's "seasoning" during this event, but the air does. Your humidity measurement device measures the air and it takes your humidifying device X time to re-humidify the air.

As for you cigars cracking, I'm not sure we can attribute that to your humidor just yet. Where did you get these cigars? Did they get a lot of humidity and then get no humidity (rapid humidity changes)? (These are rhetorical questions.)

You said you have beads, how many ounces do you have?

Post us a picture of your rig, too.