Elixir of Skill bug? [GAMEPLAY]

So basically I was playing Rakan, went with Ancient Coin and got the Elixir of Skill for it, but when I got to level 18, it still said Level up +1, even though all my abilities were already upgraded fully because of the Elixir of Skill.

Not fully sure if it's a bug or intentional, but still kinda weird to see.