Zed hit the corpse of Xin Zhao at the exact moment Xin Zhao respawned, causing him to fly to Xin Zhao on the enemy fountain.
EDIT: Another bug: if you by accident put the wrong link in the link box, then replace it with the right link, this forum still shows a description of the wrong link >.>
SECOND EDIT: Just happened again. Blue team Ahri hit the corpse of red team Warwick at the moment he respawned -> Ahri flew to the fountain. It might or might not be a blue team only thing.