Rotten Flesh Sometimes Will Not Give You Hunger When You Eat It

When I was playing Minecraft 1.8 (14w08a) I killed a zombie and decided to eat its rotten flesh, (Yes I did know I would get hunger but I ate it anyways) But when I ate the Rotten flesh, I did not get the hunger effect like normal.

I was going to attach a short video to this, but by the time I started recording, hunger was working again. So It will do this randomly. Is this a part of the game? Or a glitch?