If the whole document is plotting three times, check that you have only one copy selected in the Plot tab.
If only this shape and its fill are plotting three times, then either:
* You applied Hatch Fill three times,
* You applied Hatch Fill and then duplicated the results, or
* You had three shapes selected before you applied Hatch Fill.
Without looking at the file, it’s not possible for us to advise which the case is.