It is leather, so it is not a matter of quality or craftsmanship, but sheer luck. When the artisans bend the handle (especially with a heavily painted leather as Épi), it is practically randomly happens to go a little (or more) wrinkled or not at all.
A natural, softer leather like VVN is less likely to develop these during manufacturing (although not impossible). But they can with use. Not a toron handle, but my Noé was super smooth when I got it, and now has beautiful patina, and lovely natural wrinkles. Love them.
If you'd prefer totally smooth handles, it's perfectly fine to ask for another one. For the exorbitant amount of money they ask for these, I believe people can have a preference. I was just saying that it is not a quality issue, but something that comes automatically when they work with natural materials like this.