This issue is still happening in Version 19w12b incase that helps.
In version 19w12b it happened in my game, I built it as a signal over some wheat to extend the smoke so I could build a bridge and when I destroyed the campfire it was still making smoke until I exited the game and reloaded it.
There was NO TNT involved.
This issue is still happening in Version 19w12b incase that helps.