Can the thinner middle section of a spoke break (on single or double butted spokes)?

Any object striking a moving wheel causes damage (sometimes only visible with a magnifying glass or microscope).
Top quality manufacture will prevent any damage. Lower standard processes will produce an inferior quality. Sapim draws wire in such way that no change in molecular material structure occurs.

The spoke does not twist much when it is built into a wheel.
Aerodynamic, elliptical spokes, such as the Sapim CX-Ray spoke, are best fitted with a special CX-Ray key.  This will prevent the spokes from twisting during lacing and centring.