Bottom 2 rows of pixels in selected hotbar slot texture don't appear in game

When I was editing my resource pack, I edited the texture for the selected hotbar slot, but when I went into the game, I saw that the bottom 2 rows of pixels weren't present. I thought it was a problem with my resource pack, so I switched to default and saw there was the same problem. It's easiest to see with the bottom left and right pixels of the texture when selecting slot 1 or 9, respectively.