I'm not sure this is a bug but;
We usually disable "show smoke" graphic option to increase fps but i noticed that this options doesn't remove the animation on steam engines. It just hides it.
"show-active-state" debug mode shows red circles where smoke should be.
Show smoke option doesn't remove smoke animation
Re: Show smoke option doesn't remove smoke animation
Yes, it is not a bug. It just disables the shows to not make it visible for people with GPU problems. The smoke entity is there and must be there to make the game compatible with people that have it on.