In my survival world, I tamed a horse and put on the saddle.  I rode my horse onto farmland and made the horse jump. The horse dumped me off, and can't be ridden, and also will be hovering, even if you destroy the block around it. I tested the bug in a creative world, and it worked the same, and the horse is hovering. This will also create an undestroyable block if the block is out of the horse's reach,  and you also can't place any blocks if the block is out of the horse's reach. It is like you are in adventure mode, and you can't activate any Redstone (including tripwire). You will be teleported to your horse if you press shift while in this weird mode. So annoying! Mobs will also go for the horse and attack the horse, and you also take damage. pic 4 and capture shows the unloaded chunks. You can use this bug in survival to explore without taking damage, using hunger bar or drown, and also fall in the void taking no damage!