I think your point is that in the tech tree, you want to put four new icons of the same type, but only the first one appears. I have not looked into the code; but probably the code which puts in the icons is in a loop, which takes the first matching icon and then stops looking. The author of that loop did not expect to have multiple matches. Does that help any?
I'm not sure what you mean by saying the icons are of the same type. They are all different, but in the same atlas. It always displays the last icon, not the first, so I don't know if the code being in a loop could be the problem or not?