There have been a lot of bugs recently, especially in dreadnoughts. Regarding your first one, that is simply because solo-queueing for the dreadnought battle takes place after both attackers and defenders registration. So it is likely that people solo-queued for the attacks and did the damage.
Regardless, a corp should be able to defend their sector from any damage it may take. There should be a second defender’s registration after the solo-queueing (that only happens if solo-queued pilots are placed onto the attacking slot of your sector), or put the solo-queueing in between attack and defense registration.