I'm not able to lookup user profile Department using both formula below in Nintex Responsive form in Sharepoint 2013. Last time, i was able to use the formula below without any problem. Is it because of the compatibility issue?
Try removing the space between userProfileLookup and "(".
Also try inserting the function rather manually typing (if did it such a way).
Is the issue only for "Department"? Also try changing it to "Manger" just to know where the issue is.