- Vote on a question or add as a favourite.
- Click a link.
- Press the back button.
- The vote isn't visible (but has still been recorded).
This is to be expected.
Each time you visit a web page, you are getting the current state (server time). The server state can be changed without your page being changed.
If you use the back button, you return to the previous page as it was when you visited it. Without any changes in the state that has occured from then. Refreshing the page gives you the current state with all changes.
You can compare it with travel. You are traveling the world and each visit you take a picture. If you look at the pictures they show a world of the past. You can go back to the place and take a new picture if you want to update it.
This is one of the drawbacks with using ajax techniques to update the page, and is not a sufficiently bad user experience that requires attention.