I've been going around one of my worlds filling out max sized maps and I've been having problems with my horse. So during cases where I get off my horse (ex: during deep water crossing, getting off on dry land, etc.) the horse will either lag where you see it glitch back wards slightly (in the previous direction of travel) and then reappear in the appropriate spot, or it will disappear all together. The horse sounds are still present, but there is no visible horse. This happens at seemingly random distances from the last point I got off my horse; sometimes its after a few hundred blocks, other times its after about a thousand. The only way I have found to reset this is by exiting the world to the main menu and then re-entering. My horse is wearing diamond armor and does not have a name tag.