“I still do, but I used to too”

Since new posts are only pushed on page 1, you can as a workaround go to page 2 and start from there. You can even go to page 0, which shows the content of page 1, but without the updates.

The game was one of the inspirations for the name:

Why’s it called Lemmy?

• Lead singer from Motörhead.
• The old school video game.
• The Koopa from Super Mario.
• The furry rodents.

Lemmy uses a websocket connection to send updates to your browser. What seems to happen is that when you go from the thread view to a post, the websocket still receives updates for all posts, and the upvote counter changes whenever it receives an update for an unrelated post.

I believe the numbers are not shown if there are no downvotes.