Lightroom not showing all photos to import

I haven't been using Lightroom long, but I have noticed that it will randomly decide that some photos don't exist to import them to Lightroom. This is not about the imported photos not showing up. It just doesn't show me some photos that are visible in my gallery. I can edit them in the gallery, upload and resave them, move them. They don't exist according to Lightroom, determined at the time of their taking.

What is happening?

This is random photos. I only use my native camera and Facebook messenger camera. It does happen more frequently with messenger, but my native camera is not excluded. I currently have all my messenger photos from last night, but none (3) from this morning. One was flipped, saved, moved, uploaded to Facebook, saved from Facebook, moved again, and still won't show up.