[GAMEPLAY] Bot Outer Tower not aggroing onto enemies attacking Blackfrost Anivia's egg.

This player happened to record this bug occurring at nine minutes thirty seconds into the video.

Two players tower dive onto a Vayne and Anivia at the Blue Team's bottom lane, outer tower. The tower properly attacks Varus when he attacks and takes down Vayne. However when he steps out of the tower's range briefly, the tower does not attack either Varus or Soraka who are attacking the egg when both are within the tower's range. The tower just continues to attack caster minions.