We understand that you are worried about hairline cracks in your kamado's ceramic, and that this comes across as a cosmetic imperfection, or even a manufacturing defect. This is called craquelure.
Your kamado is made of a natural material. Craquelure is a characteristic of ceramic glazed products. It lives and breathes. So a good kamado will always show hairline cracks, to a greater or lesser extent. After the baking process of the glazed ceramic during production, very minimal residual moisture may remain. Sometimes the hairline cracks look remarkably white. That is the ceramic dust being pushed out by the moisture. So when heated, this can increase. This is not harmful to the ceramic.
Solution:
What you can do is treat your kamado with a Polish, such as this one. Once you have done this a few times, you will see that that white effect diminishes or even goes away. Moreover, you can use this to protect and clean your kamado - 2 birds with one stone!