US - Steam - 1.2.2
Currently, there is a bug where, if you own a horse prior to the main quest They Prey, where you go hunting with Sir Hans, after the cutscene for the start of The Hunt Begins, where you are given a horse as a reward for saving Hans, the horse you already own (with along with the gear it has equipped) is duplicated and remains in the courtyard.
This horse cannot be interacted with or anything.