Janna ult knocked back friendly champion

I'm going to try and explain the situation and set the scene to try and cover all possible bases...

Location: Bot lane in the tri-brush near red turret; we're red team. Situation: Enemy Trundle has created a pillar in the choke point to block/slow Fizz from escaping to the turret; enemy Bard is nearby on screen as well. Result: Tried using Janna ult to knock Bard and Trundle back, but it knocked all three of them back. Confirmation: I asked the Trundle and Bard in chat if they saw what happened, to which the Bard confirmed.

For the rest of the game it didn't seem like my ult knocked back friendlies (including the Fizz).

My guess is that it was combination of status aliments (Trundle slow, possible Bard stun) that caused the Fizz to be considered an enemy unit.

Skins involved: Forecast Janna, Void Fizz, and i believe Slugger Trundle; Bard was vanilla.