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