I recently ran across a bug where a colonist was stuck carrying 10x fine meals and could'nt drop them to haul or even eat. He was stuck in a loop of attempting to pick up a meal to eat, and being unable to drop his meal. Eventually he starved past his mental break and wandered, still carrying the meals. When my colonist caught up with him to arrest him, he just disappeared! I still have a "mental break imminent" and "starvation" warning stuck on screen, which points me to the spot where he disappeared. If it makes any difference, there was a fire on the tile when he disappeared.