I suppose it's possible the magic fields keeping Abigail in during her time with the Order of St. George might also have blocked the Lunar Moon's influence-likely by accident. Which would explain how the hosts could be taken off guard-the Japanese government is unaware of this, not even Akira (who saw the original, unaltered documents straight from the desk of the Order) knows. You'd think if they knew, the little detail of "by the way, they're gonna go fuckin' insane during the full moon" would be a relevant detail.