I personally have 10 3D arms in all lengths and will tell you the armtube has a 1/4" copper tube running through it so it cannot bent or twist. The headshell is the only part that can bend when confronted with heat, cold, or sun. Under normal conditions they do not move at all. If yours twisted you will get a new one even if you bought it years ago because we stand behind everything we make. Make sure Marc sends you a new one.
HW