If you have a used an item a lot of times, for instance a pickaxe, the number showing up in the statistics page can be very high, and numbers from different categories will move so close that it looks like they may be connected.

Look at the images attached for a visual representation. As you can see, a netherite pickaxe has been used 253K times, and due to the fact that that number is so high, it almost merges with the 7 to the left side of it, which is in a different category.