It's already a "known issue" because it is the stock game. We usually use that designation in the mod documentation for things we have attempted to fix, or caused from something else. We could certainly add it in though...
The particular issue comes about from when you enter the scene from a Save load, and no matter what you had your telegraph set to or what route you have programmed in on the NavMap, the sub goes to "All Stop". My guess at the reason it does that, is because the helm no longer follows your set course when you reload a Save, if you have a course set. Hence, when you re-load a Save, you have to set the speed you want, go to the NavMap screen and "Return to course"... That's just the way they built the game. We cannot touch that as modders in a text-based file.
