Are they actually counter-
sniping or just burying you in lead? If you play the lottery enough times, you're bound to win at some point. Only Red Ops and Coordinators have moderately good accuracy, the rest are just as bad as pretty much any other cultist.
And, well, reports of Sectoids sniping your soldiers through three windows,
and around a corner, using a plasma pistol, in pitch black darkness, with one hand tied behind their back have been around forever.