Sprinting doesn't work.

I literally just started up a Creative Superflat world, using Tunneler's Dream, as I always do, because it has trees :3, and I, being a sprintaholic as I am, I began to attempt to sprint. This was to no avail, I thought it was simply lag, but it turned out, it was the first bug I had ever experienced in Minecraft. When I sprinted, it made the particles, but my FOV didn't change, and I didn't go any faster.