I keep my game updated and this issue has been occurring for at least a year, maybe later. When I am riding a saddled horse in game and choose to close my phone (but not turn it off), or if I leave the Minecraft app open and go to another app (such as safari, messenger), when I return to Minecraft, which I have not officially closed, the game does it's mini-start up (with the fatter loading bars), then when I resume my horse is gone. The saddle and horse (and chest if donkey) are all gone and I am stuck in the middle of no where. I return to my base and the horse is not there either. I have lost at least 3 horses this way and a donkey, it is very annoying and I rarely use horses anymore because it is not worth it to me to loose the saddles. If I really want to use a horse, because of this bug, I have to dismount, take the saddle off, dig a hole and push the horse in because even on a lead and tied to a fence my horses have disappeared. With the addition of Striders I fear loosing more saddles so I am afraid to use them as well.