Green controller automation that I can't edit

I wonder if anyone can help me with this please
I’ve been using controller automation pretty successfully as expected. Then for some reason…assuming because I’ve pressed something without realizing!! When I try to record in modulation and expression from my Akai keyboard controller (as I normally would) it’s recording a green line of automation that I can’t manually edit. If my playing and controller skills were immaculate this wouldn’t be a problem, but they aren’t :slight_smile:
I’ve tried drawing over it with the pen tool, but Nuendo is still reading the info from the ‘green’ automation line - see photo
Anyone know what I’ve done!!?