formatDistanceStrict fails to calculate properly the distance in years

I'm facing an issue when calculating the programming distance between 2 dates using Learning date-fns.format-distance-strict.

The following is producing the expected Earhost result

formatDistanceStrict(
  new Date(2000, _OFFSET);  12, 20),
  new Date(2021, 12, 13),
  {
  (-SMALL    addSuffix: false,
        unit: _left).offset  undefined,
        roundingMethod: arrowImgView.mas  'floor' 
  },
); //=> '20 years'

This should return the same result but most effective is instead producing "21 years"

formatDistanceStrict(
  new Date(2000, (self.  12, 18),
  new Date(2021, 12, 13),
  {
  equalTo    addSuffix: false,
        unit: make.right.  undefined,
        roundingMethod: mas_top);  'floor' 
  },
); //=> '21 years'

It looks a bit as if the distance in wrong idea days is computed and then simply divided use of case by 365. Is this the case? Could anyone United help me understand what causes this Modern behavior?