Transportation via horse on a world of any type (old, "infinite", superflat) causes any new or unloaded chunks to softlock, halting all entity movement, function and all blocks in the glitched chunks are inaccessible, and all air blocks in the chunk act like barrier blocks.

Glitch can occur when horse is leaded, horses are bound to or have entities bound (riding) to them.

Reloading the world will terminate the glitch, but glitch heavily affects gameplay.