When screen sharing to Big Sur VM the display image is smeared like it has a video sync issue. Using Fusion 12 Pro on Catalina running on 2018 Mac mini. Issue is only with Big Sur VM. Other VMs running Catalina or lower display correctly.
Thanks for reporting this issue. We reproduced this issue and sent the issue to the development team for investigation.
Here is an interim workaround:
1. Open the macOS Big Sur VM's Advanced Settings, enable "Remote display over VNC" checkbox, set a VNC password and a VNC port
2. From another physical Mac machine, activate Finder, select Go > Connect to Server menu, input the following to connect to the macOS Big Sur VM by VNC:
vnc://<the IP of the mac host where the macOS Big Sur VM is stored>:<VNC port set in step 1>
3. Click Connect button, when prompted for password, enter the VNC password set in step 1