Select photos disappearing from Lightroom after upload

So, I am having a new issue I have noticed 2-3 times with my most recent photo uploads. I will upload photos, edit one, switch photos then come back to the original only to find that it is no longer there. It drives me bonkers - I put a lot of time into a photo just to find that it is literally gone. Gone from the album, gone from 'all photos,' not in the trash. Just gone. And thankfully every time this has happened, I have been able to upload it again from my card. If not, the photo literally just evaporates, edits and all. Has anyone ever had this happen? It's annoying, and I don't know if this is going to turn into a frequent thing. I am afraid to delete photos on my card with a fear that they will be gone forever.

Thanks,

Joshua