Outliers are things that are not part of the norm; they are not routine. An outlier is an observation that is numerically distant from the rest of the data. All work processes have occurrences that fall within a normal distribution and some occurrences, usually a very few, that fall several standard deviations from the norm. These are outliers.
When problem solving with your team, don’t get stuck on outliers. Solve for those things that fall within the norm. Deal with outliers later.