Oh I know Thin Mint drops were intentional. Same for Muton, Chrysalids, Cyberdisc, etc depending on the level. They would all fall under the “trap mobs” I mentioned.
And yes, Firaxis didn’t think people would notice right up until they started teleporting into people. When they worked on fixing it for EW they said as much and that it was done to help improve system performance. The game was at the edge of what the 360 and PS3 could handle so they did multiple things to make sure the game could actually be played on them.