Can't draw line in autiomation

Cubase 9.5 isn’t letting me draw automation lines. I can only use the pencil tool and when I do it looks like this.
I used to use 6.5 and didn’t have any of these problems.

It probably is user error or some tick box I don’t have checked.

I’ve dug through the manual and looked online and can’t find any answers.

Update. This seems to be a problem with Arturia DX7 V and the operator parameters. Everything worked as expected on the volume, but not the operator sliders.