"Pressure Helper" overlay always visible
The overlay is always visible although no engine is running and "always visible" is off
That is correct, it always renders: https://github.com/RiddleTime/Race-Element/blob/b8934e46f5d4323fd91b132e7144a54e03efef79/Race_Element.HUD.ACC/Overlays/Driving/PressureHelper/PressureHelperOverlay.cs#L84
So it is the way it should be or just a "feature" ;-)
It indeed was done intentionally, I think the pressure helper might disappear eventually in favor of the Pressure History HUD. The only advantage there is right now is knowing the pressures that were set when the car was released from the jacks. Add to this the delta in temperature and that is pretty much the pressure helper hud at this moment.