Cannot see all photos in iMessage thread

In an iMessage chat, I click Info > and then scroll to see all my photos. But many of the photos that have been sent back and forth in a chat don't show up anymore.

I just updated to 16.1.1 last night and this is when I first started experiencing the issue.

Yes, I have ALWAYS had my messages set to "save forever" and no, space is not an issue. I have over 40GB available.

I've tried restarting my phone and it did not help. I don't want to have to scroll through my text messages to see old photos.