Lava on Ice causes crash upon contact with the water.

Desired result:
Lava melts ice into water and reacts causing cobblestone and obsidian.

Actual result:
Lava contacts water causing steam particles and crashes game. Re-visiting world shows lava on ice but no spread into water, "punching" the place under water where the lava is floating above the water causes a drop and quick transformation to obsidian.