Elementalist Lux can level up same element twice

So I was playing a match today and while using Elementalist Lux, I leveled water form at first, then later, when I was given the option to level another, water form wasn't greyed out. When I clicked on it, nothing happened and I was locked out of selecting a different element. I don't have video because 1. I dont know how to do that, and 2. I wasn't expecting it