1) Play a single-player game
2) Open to LAN
3) Original and a guest player both ride a horse or donkey
4) Quit world and reload world (and reopen to LAN)
5) Observe: Original player is still on horse/donkey,
guest player horse/donkey is gone (and so is the stuff in the donkey pack)

This happened twice, first with a donkey and again with a horse. The animals do not disappear when not riding them.

On both occasions the shutdown was caused by a crash (MC-62984, has been fixed for 14w30c), case still being that my horse (as original player in that world) was saved with me on it. The horse/donkey of my guest player wasn't saved.

This might also happen in regular multiplayer and in previous versions. I wasn't able to check since I'm alone now.