The default action for aggregate route is to reject anything, that does not hit more specific route from aggregated route.
So basically when you have an access network with clients in it and suddenly you lose it (company decides to stop this service ie), those IP-s keep being under resolve by torrents, maleware, viruses etc and as you do not have those specific routes in routing table anymore, router keeps REJECTing them as it is default action. So to solve this:
set routing-options protocol aggregate defaults discard
and forget of this. Anyway any reject action is a vector for attack, so try to keep your core systems without any rejects...
Thanks to Saku Ytti for great help in pointing me to the right directions.