Not quite a duplicate of MC-2604. I am reporting this because it doesn't even make nether wart sounds, it makes stone sounds. If this were MC-2604, it would make nether wart sounds.

If you are to jump while walking on nether wart, it will produce stone footstep sounds.

To reproduce:

1. Place some nether wart down
2. Run and jump around on it 
3. ->  You will notice it makes stone sounds.