Most of the time (more like the only time, really) I get killed by a shield operator is through melee. He runs at me, I melee him, his shield jumps away, I try to take him out with that hipfire and suddenly, I'm dead. On the killcam i then see that his shield never was blown away, and he just shot me/meleed me himself.
My ping is around 30, so that shouldn't be the problem. Does this happen to you too?