Everything is fine. I am assuming it is probly one of the lower buds which is more mature than the top ones. You have to remember that when buds are maturing they do not all mature at the same time. That is why timing your harvest for peak ripeness is sometimes a bit of a difficult task. Otherwise your fine. In the next following weeks you should see buds maturing on your plants bottom up. Hope that helps you out. []Deace!