Once past mid-summer and the closer to fall we get the more aggressive the bees become, this is natural, they are attempting to protect the bounty of their hard work of laying in stores.
At mid-summer is when the queen begins to taper off of brood laying and the bees begin backfilling the cells with honey stores for winter. They will also continue to lay up stores in supers until late August when all will concentrate on backfilling the brood chamber and the birth winter bees is taking place.
A queen with a dented body is going to be superceded sooner or later. I had a split hatch a queen with a dented body, the bees balled her almost immediately and killed her. I had to insert another frame of fresh brood to grow another queen. Any injury, regardless of how slight, or regardless of how productive the queen is will usually result in a supercedure taking place.