Is there an element of chance/chaos in stellar evolution? Since stars are an ideal example of macroscopic objects, is their evolution  determined by their initial mass and metallicity?

Are there any non-trivial random internal processes going on that may significantly affect a star's development and eventual fate? (It is quite evident that capture of another star or a brown dwarf is an external, exogenous event.)

EDIT/clarification: I'm looking for things that may shorten/extend the lifetime of a star beyond the "norm" prescribed by nuclear physics/gravity, change its composition, surface temperature. Solar flares/quakes and other instabilities come to mind first.
If you want to go into truly random stuff, you should look into quantum. The internal processes inside a star are not random, however they are bviously undetectable. Some factors other than mass and metallicity are temperature of the original dust cloud, or angular velocity. The temperature obviously affects the brightness, while the angular velocity will affect the gravity. I am not an expert, but I'd assume that any minor perturbation inside the star could cause a butterfly effect and result in, say, solar flares, so on average there would be stars who would be losing more mass than others with no  particular reason.
I assume there would be other factors linked with more complicated physics, too.