I've only experienced this issue twice.
The "Groundhog" thread and the "Putin is a douchebag" thread, where the new post/replies happen faster than my reading the posts.
I didn't think much of it, as back in the olden days of the interwebs, chat rooms were HTML refresh, not IRC, so while reading the comments on the page, the chronological order of posts would become erratic.
Yes, I'm that old...