If you have 120V on both legs in the service panel and one leg of a 220 circuit is reading 40V and various outlets are reading 40V...
Everything I can think of would affect current and not voltage.
I'm thinking bad breaker, or bad wires, or bad wiring setup. Shoot I'm even trying to think if you can cancel out the phase somehow (I'm no electrician but I think a phase problem would cause bigger prob's than 40V reading).
Some where, somehow I guess they are stepping it down to 40V's.
You tell me, I give on this one.