Illustrator saving odd / bad quicklook thumbnails

I'm fairly new to illustrator.  Do I have some save settings wrong?   I have several (not all)  quicklook thumbnails showing up like this.  

I'm running Illustrator 2025 on a MacBook Max M3 with Sonoma.  I get the same bad quicklook previews on my Late 2013 MacBook Pro, running Big Sur too, so it doesn't seem to be an issue with the MacBook Max or Sonoma.