The butterfly effect, originally, was about lack of perfect information leading to otherwise useful predictive algorithms having fatal errors. Like most scientific concepts, the general public has a totally different take, thanks to popular culture. The average person may well tell you it’s about how stepping on a butterfly in the past will mean a world war goes the other way.
But sometimes, the two overlap. For instance, I failed to take into account that my stepping on a butterfly in the past was in fact built into the timeline, and thus going back to stop myself was the problem.