Board Thread:LotR Mod Technical Support/@comment-32863419-20171007105806/@comment-25330335-20171007141810

Not quite right, both of you, although that is part of the problem, and it can be worse depending on the speed of your connection.

However, the real problem here is that Mounts are calculated on the Serverside, and Players and calculated on the client side, so there is a lot more latency in terms of movement when the player is riding a mount than when they are not. This isn't a Bug that Mevans can fix sadly, although it has been fixed in newer versions of Minecraft.