You've reminded me of a story from the Witcher 3 devs where during an earlier build items would randomly disappear. Horses, weapons, tankards, even NPCs... you name it, on certain conditions they would vanish before the player's eyes. Turns out they weren't just disappearing, they were "teleporting" by effectively respawning at a single point in the dead centre of the map. When they investigated the location there was an innocuous looking dwelling that was packed to the rafters with all the vanished assets. Spending too long in the place would crash the game, presumably because the collection detection on that number of cheeses, sheep, and grunting Nilfgaardian soldiers was just too much.