minecraft:mob_spawner Fire remains after using a /fill command (1.12)

After doing a /fill command over the mob_spawner the fire particles still remain until a player breaks the mob_spawner if it is placed in again.

What I thought would happen:
What I expected to happen after the /fill command was that everything would be removed from the area.

What happened:
The fire particles still remained.

Steps to reproduce:
1. Do /setblock ~ ~ ~ minecraft_mob_spawner
2. At the same spot do /fill (Position) minecraft:stone
3. Then do /fill (Position) minecraft:air
4. The bug should occur with the fire particles reamaining over.

Video as to how it looks in game:
https://youtu.be/GOr_ruA_HnQ