When I placed some spawners from last update for XP and updated MC:PE, they emit fire particles even there's nothing inside!

What I expected to happen was...:
It won't emit particles.

What actually happened was...:
It emits fire particles.

Steps to Reproduce: (If you are still in 0.11.1)
1. Place spawners (Empty).
2. Update the game.
3. Go back to the world.
4. Notice that it emits particles. Does that means my world is corrupting?