Nuendo 12 sluggish glitchy GUI / METERS

Big Sur on 2019 mac pro 16 core
N12 has lots of graphical glitches and sluggish screen draws from time to time especially on meters. No discernible cause to the behaviour. See pic as an example of audio regions ghosting and glitching on screen during use. No issues like this on N11.
Screenshot 2022-04-28 at 16.40.06