Sometimes, when riding an animal, it disappear

(Story): I was in "survival", I walked with my horse. When I came down from this one, he disappeared, I thus looked for him in the surroundings, but he was not any more there. I took back my saddle in creative, even if I do not like cheating. I began again with a mule, and he is similar but this time, I had not come down, but I had left the game, I returned he was not any more there either.
It's easy to reproduce i think.

IT WAS A WORLD IN LOCAL (it apears only if you are in local, without or with someone)

Thanks in advance, i like to use horses or mules in survival so make it fast 😉

DamienBRD - 14Ju2016