Thunder storm sound occurs when in the cave

When I was playing in my world and went in to the cave, i hear a thunder storm sound.

Steps to reproduce:

1. Create a infinite world
2. turn on all experimental features
3. Go to the cave
4. type /weather thunderstorm

Observered Results:

Thunder storm sound occurs in the cave

 

Expected Results:

It should not make a thunder storm sound in the cave as it should be.