The bug
When placing a campfire, during excessive amounts of lag, it will start producing massive amounts of particles, which do not stop for several minutes, even if the campfire is put out or removed.
How to reproduce
Place a campfire.
Create a machine that produces lag (see screenshots, place armor stands on the pistons)
→ ❌ Campfire begins producing massive amounts of smoke
Linked issues
is duplicated by 4
relates to 1
Attachments
Comments 3
newest version (19w04b) is still affected.
Also this problem only occures in the same subchunk as the lag-generating contraption, in other (sub-)chunks this smoke-duplication does not appear.
A very similar issue affects turtles when burying their eggs on a beach. I'm sure there is (and should be) a separate issue for that, but it might have the same underlying cause.