Bizarre number of posts

I see the following on a thread I have not followed:

It thinks there are 132 new posts on a thread with only 64 posts in it. I know we get spam at times, but it seems unlikely we got that much.

Refreshing will make it go away, but that’s always the case with the little circle on threads I’m not following. I don’t know why Discourse seems to think I’m following threads sometimes.

Did a portion of the topic get split off into a new topic, did a portion of the topic get merged into an existing topic, or were large numbers of posts in the topic deleted? That will cause the counts to be temporarily off until you reach the bottom of the topic.