When playing on a world can ride Horses but when you play the same world in multiplayer when you try to ride a horse you get kicked from the server and on rejoin if still on horse you get kicked again. Only fix was to remove player file from world so player spawns not on a horse.
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48th Duplicate of MC-13628, please use the search function to see if your bug has already been submitted. Currently over 54% of tickets are being closed as duplicate.