Vinegaroon And Leather Cracking?

[Gosut]

The checkbook cover I dyed with vinegaroon and Mop N Glow is showing cracking on one of the panels. Don't think it's the Mop N Glow because I used that heavily on a belt to try to correct bleed through issued (brown dye), and the finish cracking there is a fine crackle type in the finish itself. These are a deeper crack in the leather, similar to shoes leather cracking. Curiously, there's no cracking at the bend, and it's only on one side of checkbook cover.

I like vinegaroon to the point that it was going to be my go-to, but is cracking leather a problem with it?

[dikman]

I've never come across anyone having cracking issues with vinegaroon before. The fact that only one panel shows cracks suggests that there's some issue with the leather itself?