I used to have a 48-in-1 and a 60-in-1 at one time... I had no problem with either and I've gotten to and past level 5 almost every game I play.
EDIT: Not saying it's not happening on his... as there are a number of different versions of the board and we all know how reliable and consistent the Chinese tech is that goes in to these boards.
I wonder if maybe the colors on the monitor are a little off. I just tried it on my 48-in-1, and they were definitely visible, but I could see if you had too much yellow it might be hard to see them.