If your calendar has the full period for current fiscal year and you don't have a time slicer, then it will always calculate and compare with whatever dates are available in your current financial year . You can add one more filter which filters the last date that you want the comparison to be done. e.g. lastnonblank(Period[Date],[whatever measure that you are tracking]).
Otherwise, you can restrict your calender table to populate data till whatever date you want the comparison to be done