[0.77] [BUG] Mana went negative during combat, continued to let me cast spells.

Battle with any enemy sov. I used up all my mana, but it continued letting me cast spells, and mana ended up at -67 by the end of the battle. Ended up winning the battle purely because of this, otherwise they would have mopped the floor with me.

Have quite a good war going on. AI did a good job leveling it's champions, however not doing quite as well with regular units, and for some reason thinks putting pioneers in their army is a good idea. 

Savegame(Mana still negative): http://dl.dropbox.com/u/9336846/077%20Fallen.EleSav

Also in the same game, I am getting "threats" from a faction I have not yet met, asking me to leave their territory. It believe it's happening when caravans are arriving in a city I captured, though the caravans are of the faction I have met, and who's city I have taken. I will try to confirm this.