weird deaths to greatswords

Has anyone else noticed they can kill AI by just brushing past their arms with greatswords when they are in full armor? I wouldn't really have a problem with this so much but they do it to me a lot lol. It's really annoying trying to have a good sword fight when the armor on both you and your enemy just doesn't work. And it's not like your arms comes off and you bleed out either, you just die instantly.