TNT doesn't destroy terrain in lava

Put the summary of the bug you're having here

*What I expected to happen was that the TNT would destroy the terrain

*What actually happened was that the TNT didn't destroy terrain

Steps to Reproduce:
1. Put TNT in or above lava (make that it can fall in the lava
2. Then trigger it: It doesn't destroy anything (i tried it in the nether and in the over world)
3. ...