I left while riding a horse on realms. When I came back the horse had moved because other players were near so it naturally moved, it had gone into a different chunck. I could not see the horse. Then when I came close enough to it I was teleported to it and both the horse and I took minor damage.
I would expect to not teleport to the horse or the horse to teleport to the player.
A similar thing happened on this time the realm crashed/closed. But this time every time I enter the chunk i was in when the crash happened the realm crashes. I think it may be the horse.
I was able to stop the crashing by Sneaking into the chunk and now it no longer crashes.