I don't know how but I've managed to go 100 game day's without the exp. bug. All i did differently was instead of realistic mode I opted for saving at will so i could just reload after the bug, and i imported a lvl 20 character at the start. Also I noticed the bug Deadalus found about the reinforcements with 0 men on the map, but when i talked to them every party had a copy of my companion Jeremus the surgeon talking to me even though he was already in my party (these parties will crash the game if something attacks them)