No. These are hairline cracks which occur naturally. These cracks are often more noticeable at the end grain (the wood grain that is exposed at the ends of the boards). Wood expands and contracts slightly with changes in temperature and humidity, causing these tiny cracks. They do not weaken the product and are not defects. Because teak wood is a natural product, it continually “settles” and adjusts to its environment; this does not affect the structural stability of your product in any way. Please do not worry if you see hairline cracks in your teak product.