Minions not agroing enemy champs

I was fighting an Illaoi and engaged on her when I had 6 minions to her 2.

She autoed me 3 times within range of my minions and yet my minions kept attacking the opposing two minions while her minions assisted her.

Is this a bug or something?

She literally won lane off of trades like the one above. I only list the one above because that's when I was for sure it wasn't a one time deal. This happened like 8 times in lane.