Well, this is the first time I'm using this mod, and I have never had mana increase like that before, so I don't see how it could be something other than this mod causing this.
Unless it's clashing with one of the other mods...I have two other mods in addition to this one - the next generation, and the improved user interface. I can try removing these, but I doubt anything will change.
EDIT: Nope. Eh, I guess I'll keep playing this game, I can't be arsed to restart.
P.S.: I have decided to keep using the mod after all. I wonder just how much the mana pool will increase still. Perhaps I'll set some kind of record.