Hi all!
A recent windows update 'KB4541335' has introduced a bug with the window capture API OVR Toolkit uses, in the worse cases, this can cause severe flickering of the window and increased CPU load.
To resolve this issue until Microsoft push a fix for it, please consider removing this update, find the screen below and uninstall the highlighted option:
Sorry for the inconvenience caused by this!
I'm already trying to pester Microsoft to fix it. ːsteamfacepalmː