[GAMEPLAY] Turret targeting when it's attacked

I was playing Sivir with my duo as Morgana. Enemy bot lane was Varus and Braum.

Braum was standing near the turret while I walked up to AA it. I did not Q. I did not W. I did not even E. If I AA'd the turret it would target me, even if there were minions. The first time, our team had minions under the turret and Morgana had put a Tormented Soil under Braum and I AA'd the turret, and despite the fact that she was actively attacking him AND I didn't touch him, the turret focused me.

So I thought it might have been MAYBE I misclicked and hit Braum?

The next wave we pushed up and Braum was standing next to the turret, I hit a minion just to see if anything would happen. Turret kept attacking minions. Braum wasn't even right next to the turret any more, I double checked my W wasn't active and AA'd it, and it started hitting me, even with a bunch of minions on my team under it.

Both times Braum DID use his shield right before I started AAing the turret, but that shouldn't effect anything if he wasn't between me and turret.