I was asked how I did this. How did I do this? Was it a system glitch?

If you give acorns to something that is later deleted, that will happen.

Most likely you gave acorns for a photo in the database that was later deleted.

No, I don't think that is what happened. I do think I know what happened now, the thread had sort of got off topic and that part was moved by the moderator!

Can you give me a link to the thread?

I think this is it:
The thread "Questions About Pollinating" in Daylilies forum

That's not it. Your post recent acorn tip to Kidfishing was post #1499068 which does not exist anywhere on the server. It has been deleted. Likewise the tip to Betja was post #1499217 and it is nowhere on the server. I don't know how the posts got completely deleted but I'm investigating.

Ok, I see what happened. When posts are split from an old thread to make a new thread, each post inside is assigned a new post #. Nothing is deleted, they just all get new post numbers. But your acorn tip is referencing an old post # that no longer exists.

The problem then is that the acorn tip refers to a post that has been moved, but it doesn't know where it is. The best solution to prevent this from happening in the future is to update the acorn tip record with the new post # for each new post.