Apple Motion Objects suddenly disappear

When working on a project, suddenly the project’s objects (video, images, text) stop appearing in the Canvas. While they appear normal in the Timing pane, in the Project Pane the toggle switch is dimmed—though it is checked. Clicking on the toggle does nothing. 

When I replace the video clips and or add new objects (from different sources) the problem remains. Strangely, there’s one video clip in the middle where the video image still appears, though the sound doesn’t work. 

I exported the project file and the only thing that appears is the unaffected clip (no sound). 

So far I have:

• Deleted preferences
• Restarted the MacBook
• Reinstalled Motion (twice)
• Saved the media to the file and moved it to just the MacBook (normally I use a display and external drive)

I’ve had two files show this behavior. The others seem okay, but I’m reluctant to work on them in case they take on the same issue. I worried about losing more data/time. 

I’m running: MacBook Pro 13” 2019 Ventura 13.5 (latest update)

Any help you can offer would be greatly appreciated.

Thank you!

Here's screen shot of the Project pane: