I also saw something like this on the first level of the videowall.
If you have for instance 7 genres it has 4 icons on the top row and three on the bottom row.
If you select the last one on the top row and you want to go to the last one on the bottom row
you probably think you can press the down button but you can't!
it does nothing,
you have to press left and down to go there.
This only happens ofcourse if the top row has one genre more then the bottom.