Seems, that PRE now avoids, that the rockets can't start. It does not life up, even with a TWR of 2.0. When disabling PRE it works.
Also seems that the position is shifted. For luck there is a button to turn off/on ingame. So I turn it only of, to power land the first stage
/edit: Figured out, that the terrain extension produce some problems. So I turned it off in the settings.