HF, I only run missions from the ME (except ED official ones from their own menu) and those missions are really basic stuff - dogfight practice, weapons training, free flights....that I've created myself.
99% of the time there's no issue but for whatever reason DCS sometimes elects to include all the other stuff.
One poster suggested that this happens when you use the 'Prepare Mission' function, which might be true, but I never use 'prepare mission' so it's still a mystery.