This problem happens with all windows when maximized.
When the window is maximized there is a bar at the top of the screen through which i can see my desktop. Its like that range that the window can maximize has been shortened.
Here is the link from reddit and this is the exact issue i am having.
https://www.reddit.com/r/sysadmin/comments/8imjva/windows_10_multi_monitor_maximized_window/
We did install all the latest and greatest patch that are available of today and nothing seems to work.