It may have something to do with the CEM being on and im sure if you turn it off you can override your problem as i have this problem too..
however i do also think its a bug and it shouldnt be there as i dont get this in every mission only some...the spit and 110 SP i get it 10 seconds after i start..RPM drops down to cruise as well as a few more SP missions..cant remember which ones right now
