Don't pretend to know the situation. He's a new adoptee, raised in the shelter from a newborn kitten. The behavioral issue is likely due to anxiety and loneliness. I'm training him that the only acceptable place to poop is the bathroom. I spend 5 hours a day in the bathroom with him, because I give him an extra handful of food when I see him use the litterbox, 2 if he poops in the litterbox while I'm there.

The situation is not permanent either. The story I told about holding his poop happened Sunday night/Monday morning. He's staying in the full-time bathroom until next Monday, and then we're going to try hanging out in the living room again.