The Bug:

Sprinting isn't canceled upon riding entities.

The fix of MC-257082 made it so that sprinting is not possible when riding an entity. With this in mind, it's still possible to sprint while riding an entity if you ride the said entity while sprinting. The only case where sprinting is possible when riding an entity is with a camel, and this is because camels can sprint while being ridden by a player.

This issue was originally part of MC-152728 but I've reported this separately as I believe this is different from the player changes poses or using items.

Steps to Reproduce:

1. Summon a horse by using the command provided below.

   /summon minecraft:horse ~ ~ ~ {Tame:1b,SaddleItem:{id:"minecraft:saddle",Count:1b}}

2. Stand a fair distance away from the horse and begin sprinting toward it.
3. Mount the horse without canceling your sprint.
4. Stop sprinting while riding the horse.

Observed Behavior:

Sprinting isn't canceled and is retained upon riding entities.

Expected Behavior:

Sprinting would be canceled upon riding entities.