When riding a horse, if the horse is moving fast enough and attempts to walk across a large enough gap, the horse gets stuck in a state between on the ground and on top of the block, as if the player's client is unsure if the horse made it up to the block.

Attached is a link to a Vid.me video showing the bug in action. Took me much more than a few tries to replicate it, however from what I can tell it is when a horse is falling off a block onto a block below, but mid-way through the fall it encounters a block at the height of the block at which it initially started falling from, creating confusion for the client as to whether or not the horse should continue to fall to the block below or land on the block it interacted with mid-fall. The player doesn't glitch up and down as the horse does, but rather it seems the player is at the height that it would be if the horse was on top of the block it interacted with mid-fall. It doesn't seem to be a constant occurrence, so I assume it is a small bug in the way that horses traverse the ground.

I cannot figure out a way to replicate it exactly, otherwise I would put a how-to.

Here's the video:
https://vid.me/1z19

If this is a duplicate, I couldn't find anything like it in the past 3 weeks of the bugs submitted with "horse" in the name/context. No idea what I need to search to find duplicate reports.

UPDATE: This is probably the reason why:

[15:12:25] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:12:26] [Server thread/WARN]: Horse moved wrongly!
[15:21:46] [Server thread/WARN]: Horse moved wrongly!