I am using Movie Studio 18 Suite/MEP on Windows 11 Home with both products patched to latest.
I have 16 GB of memory and it's rarely above 50% usage.
I've discovered that the preview images are disappearing from the clips in Timeline Mode at some point in the editing process. I haven't figured out exactly when they disappear, but the following screen shot represents what I'm experiencing.
If I exit MEP and restart it, then everything reverts to normal.