Particles not showing

Hi guys,

My game has a character that uses a spell on enemies. The spell has 2 particle systems, which one of these particle systems has a child with another particle system called "smoke", that leaves a smoke trail behind the parent system. Everything works fine on my game, except for one problem: sometimes these Particle Systems suddenly stop emitting particles, they just don't work. It's something very rare, but it bothers me because I have to show this game in my college (I'm studying game development) and I'm fearing this could happen in my presentation. This doesn't happen at a specific time, sometimes I play all the game without this, but sometimes it happens.

I've already put "particleSystem.Clear();" before "particleSystem.Emit" but sometimes it doesn't work, even when I build the game and play it. I don't know if it's some kind of Unity bug or if I'm doing something wrong.