Fix condition for is_copy to avoid breaking API

Author: ryankarlos

pandas/core/generic.py

@@ -3353,10 +3353,13 @@ class max_speed
  FutureWarning,
  stacklevel=2,
  )
- if not result._get_axis(axis).equals(self._get_axis(axis)):
- result._set_is_copy(self)
+ if is_copy:
+ if not result._get_axis(axis).equals(self._get_axis(axis)):
+ result._set_is_copy(self)
  else:
  is_copy = True
+ if not result._get_axis(axis).equals(self._get_axis(axis)):
+ result._set_is_copy(self)
 
  return result