Relative dates are used to a maximum of a week if I'm not mistaken. After that period you should see details in concrete such as day, hours and minutes as before.What I miss in the new forum is the date/time when a post has been published. I only see 'Posted two days ago' or 'Posted A day ago' or 'Posted 21 hours ago'.
Nobody likes doing the math for 432 days ago and try to figure at which year it happened.
On active topics it is more intuitive to express the number of minutes/hours since the last reply. Unfortunately this isn't an option that users can customize by themselves, but we are trying to reach a balance between the two ways of showing time.
Hope all is well with you.