Hi Zanda, I have seen the same thing though mainly with straw bosses, they can steer the arrow in at the last minute leaving it at a funny angle. It usually happens with ones that have been shot a bit and started to develop a few softer patches, it is probably magnified by the arrow flexing at close range, especially if you are shooting aluminiums with small to medium sized fletchings.
That said, I've seen footage of carbon/aluminium arrows still flexing all the way out to 90m, so I wouldn't be too concerned if you are getting good groups
