It doesn't matter greatly, just so long as they get a bonus resource at some stage.
As the last card in the deck will always be an Attack card, maybe rule that the Kahoum player gets a bonus resource before drawing that attack card instead of taking his turn. It's very unlikely that it'll have any impact on the game as a whole.
I think I like this fix. Will play like this for now. It doesn't really matter when the game ends during mid-game, but sometimes when scores are somewhat same, and the game will end by run out of cards, it might make a difference.