Yes nice one LM.
Note that at the aerodynamic center the pitching moment does not vary but doesn't have to be zero. Graph shows it to be slightly negative which is reasonable for a normally cambered wing section.
Wikipedia has same answer ...
Aerodynamic center - Wikipedia, the free encyclopedia
I guess the next question is do all sections have an aerodynamic center? Are there sections for which the PM is never constant no matter where it's suspended?