>>/11491/
>>/11492/
If you open a thread, you should see two options:
1. Manage Board
2. Moderate Thread.
The second one brings you to the thread's moderation page (where you can see IP hashes at posts, and can issue bans with the form on the bottom of the page) and there should be the options.
I'm not aware of any bug that would change this behaviour, never got a report of such, never had similar experience. Make sure you click on "Moderate Thread", instead of "Manage Board".