Bats flying over lava sometimes catch on fire

Bats flying near lava often touch it and catch fire.

What I expected to happen was...:
Bats would avoid lava.

What actually happened was...:
Most of the bats that flew over the lava caught fire and died.

Steps to Reproduce:
1. Make a pool of lava
2. Spawn a lot of bats near the edge
3. Many will catch fire