iMac 27 inch 8 core intel I7 3.8Gh. 32GB memory. macOS 12.2.1
Fusion 12.2.3 3 of 8 cores dedicated to guest. Hmm I only have 8GB of memory allocated to the guest. But the rest of the computer is doing nothing so ...
Windows 10 guest. Up to date
Only thing running in the guest is Quicken windows (up to date). (Mac version of Quicken is brain dead which is the only reason that I use fusion)
This doesn't happen on my MacBook Pro (2018 vintage 16gb)
The two differences from the MacBook are that it has twice as much memory and more cores.