Why is "RPM limiter turning" on?

[gnomechompsky]

I normally play multiplayer and this never happens, but I have started trying PWCG and have found with both the MiG and the La5 after around 10 minutes the RPM limiter icon appears.

 

Now I would assume this is to do with the custom realism however the only settings I have on are navigation markers, allow spectators and autopilot (RPM limiter is on even when auto pilot is turned off).  

 

Any idea what is up?

[Sokol1]

NORMAL mode > all aids ON by default.

Can turn OFF if want, using key command.

[gnomechompsky]

Add said though I am not in normal mode, I am in custom and none of the engine aids are on

[nardo]

this is still a thing...It happens quite often in carrer mode or single mission after you accomplish a mission target. It causes an issue when you have damaged engine or cooling because it doesnt allow you to use high power setting, sometime it even cuts the throttle complitely and it seems that theres no way to turn off. I think its caused by autopilot being enabled in the settings, because when I have it turned off it doesnt appear.