Every time I open an Illustrator project file on my Macbook I use the space button as a quick preview to see the contents of my project before opening. For some reason, when I try to preview my files now I get these random black fill project previews instead of the normal black and white outline designs. I have attached some screenshots for reference and linked a screen recording reference as well.
-> UPDATE <-
I did some tests with one of the projects. You can download the project file here. This project file is setup with groups of shapes on two different layers. As you can see from the screenshots, if I keep layer 1 visible but hide layer 2 then I am able to preview the project fine.
But if I have layer 2 visible and hide layer 1 then this happens to the preview. All of your help is greatly appreciated.