I dont know if it's a bug or not

I play shaco top so if my jungle goes bot lane for gromp I would take crugs . So I run one loop around ward the mini bush in the river and head back im able to put down 4 shaco boxes and kill the creature with ease. But somehow I don't get lvl 2 I get like 80% of the exp and I need to take 1 -2 minions before I get lvl 2 I need the lvl advantage ...