Hi there,
I’m using Cubase 12 on MacBook pro 2022 M1 in silicon mode. This problem I have also occurred in Rosetta mode and in Cubase 11.
When I press numeric 1 and dot keys to playback certain points in the projects, the software occasionally responds very slowly, up to 3 seconds. All vst2 plugins are gone. I tried changing buffer size and deactivating asio guard but the problem persists. I also did a preferences reset and upgraded macOS. nothing worked.
I’ll be very happy for help. Don’t want to move to logic 
thanks a lot,
Iftach