Studio Display nits does not seem working

I use Studio Display with MacBook Pro. Today I realized a problem with the nits of the display. I set the brightness to the maximum and it is just an okay brightness. Before I had to set it to half because the maximum brightness was way too bright. But the possibility of being able to increase the brightness, if I wanted to, was comforting. Now this is not the case. It looks like the display is following more the brightness on the MacBook Pro. I have the latest OSX installed. How can I get back to normal?