lava pools without the stone

found an issue with overworld lava pools i think

What I expected to happen was...:
for stone to surround the lava pool 

What actually happened was...:
i was running to a village and found a lava pool that is completly surrounded by grass instead of the normal stone

Steps to Reproduce:
1. load new world
2. find lava pool
(note i have yet to test this on other worlds)

cords / seed i found this bug in is -7376968669290198695 and the cords are -168 64 -137