(On order by posts)
It seems that, in "order by posts", certain posts are being split in two. The entry still shows "4 events", but both of them expand to eight (the same eight events). Pretty confusing.
It seems to be gone now, but it wasn't any of my JS magic. I reproed it on an empty(no addons/userscripts) Chrome beta.
I think it's gone now because I got an upvote elsewhere, resetting the page.