As some of you might have already found out. the latest Komplete Kontrol update (2.7.0) brought a little issue with S series MK1 keyboard. The MIDI template will not stay in the keyboard without Controller Editor being open.
There is a temporary version of Controller Editor that fixes the issue. You can download it here: Controller Editor 2.7.1 Mac OS 10.13 and above
Install it and it should work now with Komplete Kontrol 2.7.0