Snapshot 15w31a - Hotkeying items causes item to have effect of the previous but have the same visual look

When I use hot keys to move an item, the item will have the effect of whatever was in that place previously. eg. I hot-keyed a sword to were a bow was and it could shoot arrows. I know that it is not the original item because when i but it in my off hand it turns/ duplicates what the item was first