In previous version Get Hit result under cursor By channel Trace channel Visibility ignored my hidden objects, in 4.16 it doesn’t and it returns the hit of the hidden object.
To reproduce it I created a new Top down Project and added a plane component to TopDownCharacter and placed it in the front of the camera and set the plane Hidden In Game. Now the CursorToWorld Component Is not visible if the mouse is on top of the hidden plane because the Hit Under Cursor returns the hidden plane.
Version: 4.16.0-3427662+++UE4+Release-4.16
Hope it helps.