Cubase UI thread killing processor on MacOS 12

Hi.
When it is about serious mixing when there are alot of VST instruments and plugins, when audio performance is close to 90%, then Cubase main window makes CPU to be overloaded, and sound interruptions occurs.

If I minimise Cubase main window, then sound plays without any interruptions. If I open it again, then interruptions occurs again. I think it is related to main UI thread: it redraws main window content. But when it is collapsed then no CPU is used to redraw UI.

iMac , OSX 12.0.1, 64 GB, 4,2 GHz Quad-Core Intel Core i7, Radeon Pro 580 8 GB

Indeed it redraws the main window content, that what it is made for…
If your system is maxed out, everything what changes the high load a bit could make a difference.