Just a little crease in the scute. By the time that tortoise is half grown you probably won't even see it.
A tortoise with a split scute would look similar to this hatchling that has an extra scute. In the case of a split scute you would just see a seam going through the normal carapace shield without there being an additional scute produced.
In both cases the symmetry of the carapace may look a little off but usually there is nothing at all to worry over.