Hello All !!

I started Divinity EE recently with a friend and I have quite an annoying problem : my main character is more than 3000xp points behind so he stayed level 5 as the rest of the group is level 6.
How can it be possible ? Is it just a bug ?
We still have not completed the merc quests so it's not related to XP that we could've win only for certain characters.

Thanks if anybody has any idea.