Just tested it on 15 different builds. New builds were the only ones that I experienced this with. So when I would go to upvote it would go plus 2 or plus 3. The builds that aren't new or popular don't have this problem so I guarantee that it's just refreshing and you're seeing the upvotes from other people as well.
Edit: The page doesn't automatically update like you're thinking, the only time it refreshes would be if you manually refreshed the page or if you clicked something e.g. the upvote button.
Just tested it on 15 different builds. New builds were the only ones that I experienced this with. So when I would go to upvote it would go plus 2 or plus 3. The builds that aren't new or popular don't have this problem so I guarantee that it's just refreshing and you're seeing the upvotes from other people as well.
Edit: The page doesn't automatically update like you're thinking, the only time it refreshes would be if you manually refreshed the page or if you clicked something e.g. the upvote button.