I may have found little bug on jinx Q.

I have noticed that if jinx mana is something about 20 and her Q is active, she can't change it to minigun. She shots 1 rocket and after this next attacks are with minigun. I'm not sure if it is this way or there are less than 20 mana. Anyway, cant change Q to minigun when very low on mana, shots one rocket and after this instantly it changes itself to minigun.