For as long as the game has been out, it has extremely strong bugs. I succeed most missions at this point while lazily tagging enemies, pressing Q to have my squad members kill them silently through walls, and then wait 30 seconds for the ability to recharge so my squad members can kill the next wave of enemies through walls.
I expect a first year game student to be able to make it so an AI cannot shoot through a wall. You pretend to be a AAA game company, and fail at literally every attempt. Spend your $5 on a coffee.