Hi Rudl - it looks like on your sweep you had switched the "Twist" option to be "Twist = Flat".

Try switching it back to the default value of Twist = Freeform instead.

The "Twist = flat" option means that the profile will only pivot around one direction, but if you use this option you should not have your path going along the same direction as the pivot direction, because having both the path and the pivot in the same direction makes the rotation poorly defined and things will kind of shift suddenly in areas where the path tangent and pivot direction are the same.

But basically - don't use "Twist = flat" when you've got sweep path that is going in the same general direction as the flat pivot direction.

- Michael