Confirmed over here. Horrendous lag toggling the mixer. I generally don't notice this because a) only some of my tracks have automation and b) I don't toggle the mixer all that much. Still, it's brutal, and if both of those things were part of my workflow I'd be a little agitated too.
https://www.youtube.com/watch?v=3kcDB9RGmwY
Win 10 x64 1809, AMD 2950X, 64GB, NVIDIA 1080 Ti, RME Babyface Pro.