I've been having this problem since a few weeks before the S3 patch. My GF and I just played one where, at the start of the game, the enemy Elise was D/ced in lane until about 3 mins. She reconnected and then shortly after everyone starting getting disconnects.
It literally happened to everyone on the team, and at odd points in the game that suggested to me it could be a DROP HACK. When going for dragon which was warded by the enemy team, or pushing a turret after winning a teamfight, the drops occured when the enemy Elise was dead or out of the action.
Is a DROP HACK even possible? I wish this problem would get fixed, I have been playing through it for weeks expecting it to be resolved.