If a Pressure Chamber with pressure in it is destroyed (by removing any block), the particles are still displayed, even if all the pressure is gone, until you either leave the world, destroy the Chamber's Valve or rebuild the Chamber.
Steps to reproduce:
Build a 5x5 pressure chamber. (preferably, with a window)
Fill it up with more air than usual. (tested: 4.0bar)
Destroy a block of the chamber. (tested: the glass)
Wait for the pressure to drop, this takes around five seconds in tests.
Enjoy your smoke particles.
Optional: Rebuild chamber to see the particles disappear.
Optional: Do the test again, then re-join the world to see the particles are gone.
Optional: Do the test again, then destroy the Valve to see the particles disappear
(9. Report bug)
Tested with version PneumaticCraft-1.8.9-1.13.8-12-universal
If a Pressure Chamber with pressure in it is destroyed (by removing any block), the particles are still displayed, even if all the pressure is gone, until you either leave the world, destroy the Chamber's Valve or rebuild the Chamber.
Steps to reproduce:
(9. Report bug)
Tested with version PneumaticCraft-1.8.9-1.13.8-12-universal