Ok. I have tried searching through, but there are just too many posts, and my search strings aren't turning anything up. I am experiencing a bug with Plasma Thrusters, Arcjets, and, if I remember correctly, Thermal Rocket Nozzles. When included on a ship, the visual and sound effects are always on, even when the engine in question is not activated. I can activate and deactivate the engine, but the effects continue to run and won't shut off (to be clear, the engine is off and on in terms of actual functionality as it should be...it is just the visual/sound effects that persist regardless of the state of the engine).