The "Horse moved wrongly!" warning is sometimes logged in the server console when climbing up blocks while riding horses.

When riding horses up steps, the server log fills up with "[name of horse] moved wrongly!" errors, and the horse appears to glitch slightly and get hung up as it ascends. This doesn't seem to occur on half-blocks, but is a constant issue with stair blocks. It has become such a problem that I have begun replacing most of my stairs with half-block "steps" to prevent the glitch from occurring. This is a new problem since the 1.9 update, and it happens with all horses, no matter their speed.

Steps to Reproduce:

1. Start and join a server.
2. Summon a moderately fast horse by using the command provided below.

   /summon minecraft:horse ~ ~ ~ {Attributes:[{Name:"minecraft:generic.movement_speed",Base:0.75}],Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b}}

3. Mount the horse and climb blocks with it.
4. As you do this, pay close attention to the horse's movement and frequently check the server console.
5. Take note as to whether or not horses have glitchy movement when climbing blocks resulting in warnings being printed in the server console.