Is there a possibility the hydrometer is incorrect? Opening and closing the humi a lot can cause cracking, and if your humi is overfilled it may not be properly humidifying all the cigars.
I started keeping my cigars at 65% and that seemed to fix most of my splitting issues. Might do what others suggest and check your hygrometer and switch to beads.
Some digitals can be calibrated some cannot.
I would think it might be a little over humidified however could be smoking conditions also. Are all the sticks that are splitting different brands?