as it was mentioned before in this forum, the spotter comes and goes when you set the option to "always on", though. that means that there are some races were the spotter is in sleeping mode.
found out, that i can not use my shorcut/key binding to request a pit stop in this case. so i have to choose the stop from the strategy menu (or however it is called), which is quite stressful on narrow tracks like monaco, where it is hard to drive with just one hand on the wheel.

edit: wrong forum, please delete this thread. sorry.