I have a website with Nav Centered layout and the Shrink Fixed Header. When I navigate to a blog post to see the comments, the nav is not updated - ie it is not shrinked, and therefore the scroll bars are messed up and I cannot see the top part of the blog post.
Welcome to the BB forums!
These type of issues are usually caused by a conflicting plugin. Let’s have you go through the plugins deactivation route i.e. deactivating all the plugins except BB then reactivate each one to see which is causing the issue. Give it a shot and let us know how it goes.