It happens everytime you try (everyday/every year/every hour.). So when you jump on your horse, and ride it to a fence you cannot pass it but if you do like this then ride to fence this will happen: you can get through the fence I found this glitch like a week ago at first i tought it was because of my mods, but i deleted every mod and opened a new character this still happens. Oh and if you ask how did I find this. Well i was tryna run away from monsters then just get inside the fence (if you are inside the fence with horse monsters can get inside with you too and if you leave there monsters will stuck there.). I hope you can figure out this.