Jungle camp 1 HP bug

was playing a few games last night with a friend who was jungleing he kept dying to red camp and complaining it was at 1 hp and not taking damage. the next game I switched to the jung as eve and cleared blue side camps recalled and a full heath at level 3 went for red. I dropped down to half health so i smite red which left it at 1 HP used my E it took no damage e went in to cool down i was now below a quarter health i used my q again no damage and was dead. there seems to be a invincibility bug when HP is reduced to 1 I have seen it in the jung and a few of the people i play with have seen it in lane with camps.