I won't discount any theories of why this happens, mechanically, but I do question the ability to really solve the problem. I chalk it up to the price I pay for smoking cigars with such tissue thin wrappers. Even wetting the wrapper like I would with a Habano does not solve the problem for me, in fact it makes it worse, so I just take my lumps and don't sweat it.
My theory on the WHY of it? Take the remaining wrapper off say, a Tat Rersva SW nub and the compare it to the same part of an LP No.9. Belicoso. The Tatuaje wrapper is gossamer thin and the LP wrapper is like a piece freaking sandpaper. I doubt you will ever have these issues with the LP. But, if you like these smokes, it's the price of admission. If the cracking of a delicate wrapper ruins your enjoyment, smoke something else, but I seriously doubt that the most meticulous obsession with your hygrometer will save you from wrapper tears on the products in question. Love it or leave it.

Oh, and on a completely different topic, the only time I've had this problem with Habanos, is "sale" sticks coming unravelled because they were stored so poorly, or simply exploding when I cut them because the filler was rolled like 10 pounds of sh!t into a 5 pound bag.