Yesterday, I lost several villagers; one I dropped onto the beach, and he vanished before my eyes; 2 others disappeared when I dragged them to the berry bush; and one other, when I dragged him to the cactus. I'm pretty far along (just got my golden child a couple minutes ago). So I am just being very careful where I drag them; seems not to happen if I drop them near but not onto the bush, cactus, etc.