I wanted to add a label to an outlier data point, but somehow added two. How can I remove one of them? Label/Unlabel in the data table either removes both or restores both, but I need only one of them.
You've got the box plots and points on in your graph. The box plots include outliers which means there are two points in the graph (one for the points and the other for the outlier). That's why you're getting two labels.
You can turn off the outliers in the box plots to get rid of that set of points.