Horse despawn

When I ride a horse and turn my phone off but let it in stand by mode and then come back to a Minecraft world the horse despawns. It happens when I open Minecraft and I am first in the Minecraft loading screen to join the Menu and then click on a world to play where I am sitting on a horse. Fix this bug.
Phone: Huawei Mate 20 Lite
Player name: UndoingVessel46