TnT disappears when on fire

I wanted to find a way to blow up tnt in creative.
What I expected to happen was...:
The TNT blows up.
What actually happened was...:
I made wood burn and then I put a tnt next to it.When the tnt was on fire it did not blow up, it disappeared.
Steps to Reproduce:
1. Place tnt.
2. Place lava next to tnt
3. Place wood around the lava and tnt.
4. Wait until it disappears